Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2022
Accounting Policies [Abstract]
Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization and Description of the Business Federal Signal Corporation was founded in 1901 and was reincorporated as a Delaware corporation in 1969. References herein to the “Company,” “we,” “our” or “us” refer collectively to Federal Signal Corporation and its subsidiaries. Products manufactured and services rendered by the Company are divided into two reportable segments: Environmental Solutions Group and Safety and Security Systems Group. The individual operating businesses are organized as such because they share certain characteristics, including technology, marketing, distribution and product application, which create long-term synergies. The Company’s fiscal year ends on December 31. All references to 2022, 2021 and 2020 relate to the fiscal year unless otherwise indicated. Basis of Presentation and Consolidation The accompanying consolidated financial statements represent the consolidation of Federal Signal Corporation and its subsidiaries and have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) and in accordance with United States (“U.S.”) generally accepted accounting principles (“GAAP”). Intercompany balances and transactions have been eliminated in consolidation. New Accounting Standards Adopted in 2022 In October 2021, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2021-08, Business Combinations (Topic 805), Accounting for Contract Assets and Liabilities from Contracts with Customers, which requires an acquirer to recognize and measure contract assets and liabilities acquired in a business combination in accordance with Revenue from Contracts with Customers (Topic 606) rather than adjust them to fair value at the acquisition date. This ASU, which is applied on a prospective basis, is effective for fiscal years beginning after December 15, 2022, and early adoption is permitted. The Company adopted this ASU effective January 1, 2022, and the application of the amended guidance to the acquisition completed in 2022 did not have a material impact on the Company’s consolidated financial statements. New Accounting Pronouncements Not Yet Adopted New accounting pronouncements issued, but not yet adopted, are either not applicable or are not expected to have a material impact on the Company’s consolidated financial statements. Non-U.S. Operations Assets and liabilities of non-U.S. subsidiaries, other than those whose functional currency is the U.S. dollar, are translated at current exchange rates with the related translation adjustments reported in stockholders’ equity as a component of Accumulated other comprehensive loss. Accounts within the Consolidated Statements of Operations are translated at the average exchange rate during the period. Non-monetary assets and liabilities are translated at historical exchange rates. The Company incurs foreign currency transaction gains or losses, related to transactions that are denominated in a currency other than the functional currency, which are recognized in the Consolidated Statements of Operations as a component of Other (income) expense, net. For the year ended December 31, 2022, the Company realized foreign currency transaction losses of $0.2 million. For the years ended December 31, 2021 and 2020, the Company realized foreign currency transaction gains of $0.3 million and $0.4 million, respectively. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities, (ii) the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and (iii) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments with a maturity of three months or less, when purchased, to be cash equivalents. The carrying amount of cash and cash equivalents approximates fair value because of the short-term maturity and highly liquid nature of these instruments. Accounts Receivable The Company carries accounts receivable at the face amount less an allowance for doubtful accounts for estimated losses as a result of a customer’s inability to make required payments. Management evaluates the aging of the accounts receivable balances, the financial condition of its customers, historical trends and the time outstanding of specific balances to estimate the amount of accounts receivables that may not be collected in the future and records the appropriate provision. Inventories The Company’s inventories are valued at the lower of cost and net realizable value. Cost is determined using the first-in, first-out method. Included in the cost of inventories are raw materials, direct wages and associated production costs. Properties and Equipment Properties and equipment are stated at cost, net of accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets. Useful lives generally range from eight to 40 years for buildings and three to 15 years for machinery and equipment. Leasehold improvements are depreciated over the shorter of the remaining life of the lease or the useful life of the improvement. Depreciation expense is primarily included as a component of Cost of sales on the Consolidated Statements of Operations, with depreciation expense associated with certain assets used for administrative purposes being presented within SEG&A expenses. Depreciation expense, which includes depreciation on rental equipment, was $41.8 million, $39.5 million and $35.2 million for the years ended December 31, 2022, 2021 and 2020, respectively. Properties and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Rental Equipment The Company enters into lease agreements with customers related to the rental of certain equipment. All of these leasing agreements are classified as operating leases and are for periods generally not to exceed five years. In accounting for these leases, the cost of the equipment purchased or manufactured by the Company is recorded as an asset and is depreciated over its estimated useful life. Rental income is recognized ratably over the term of the underlying leases. Rental equipment is depreciated to an estimated residual value on a straight-line basis over the estimated useful lives of the assets and is reviewed for potential impairment whenever an event occurs or circumstances change that indicate the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares non-discounted cash flows expected to be generated by that asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on a non-discounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. Rental equipment includes certain equipment that is manufactured by the Company and subsequently transferred to the rental fleet, as well as equipment purchased from third-party manufacturers, for the purpose of renting to end-customers. The related cash flow activity associated with these transactions is reflected within operating activities on the Consolidated Statements of Cash Flows. Goodwill Goodwill represents the excess of the cost of an acquired business over the amounts assigned to its net assets. Goodwill is not amortized but is tested for impairment at a reporting unit level on an annual basis or more frequently if indicators of impairment exist. The Company performed its annual goodwill impairment test as of October 31, 2022. In testing the goodwill of its reporting units for potential impairment, the Company applies either a qualitative or quantitative test, in accordance with Accounting Standards Codification (“ASC”) 350, Intangibles – Goodwill and Other. A qualitative approach may be applied when the Company concludes that it is not “more likely than not” that the fair value of a reporting unit is less than its carrying value. In this situation, the Company would not be required to perform the quantitative impairment test described below. A quantitative approach is performed by comparing the fair value of a reporting unit with its carrying amount. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired and no impairment charge is required. If the carrying amount of a reporting unit exceeds its fair value, this difference is recorded as an impairment charge not to exceed the carrying amount of goodwill. The Company generally determines the fair value of its reporting units using both the income and market approaches. Under the income approach, the key assumptions include projected sales, cost of sales, operating expenses and the discount rate. Under the market approach, the Company estimates fair value using marketplace fair value data from within a comparable industry grouping. The results of these two methods are weighted based upon management’s evaluation of the relevance of the two approaches. In 2022, the Company applied the quantitative approach to assess the goodwill of its reporting units for potential impairment, using a combination of the income and market approaches to determine the fair values of its reporting units. The fair values of the Company’s reporting units exceeded their carrying values by more than 20% and, therefore, no impairment was recognized. The Company had no goodwill impairments in 2022, 2021 or 2020. See Note 8 – Goodwill and Other Intangible Assets for a summary of the Company’s goodwill by segment. Intangible Assets Definite-lived intangible assets are amortized on a straight-line basis over the estimated useful lives and are tested for impairment if indicators exist in a manner similar to that described above for Rental Equipment. Indefinite-lived intangible assets are tested for impairment on an annual basis at October 31, or more frequently if an event occurs or circumstances change that indicate the fair value of an indefinite-lived intangible asset could be below its carrying amount. In testing the indefinite-lived intangibles assets for potential impairment, the Company applies either a qualitative test, or a quantitative test, in accordance with ASC 350. A qualitative approach may be applied when the Company concludes that it is not “more likely than not” that the fair value of the indefinite-lived intangible assets are less than their carrying value. A quantitative impairment test consists of comparing the fair value of the indefinite-lived intangible asset with its carrying amount. An impairment loss would be recognized for the carrying amount in excess of its fair value. In 2022, the Company performed a combination of qualitative and quantitative impairment tests over its indefinite-lived intangible assets. The fair value of the indefinite-lived intangible asset that was quantitatively tested for impairment exceeded its carrying value by more than 50%, and, therefore, no impairment was recognized. Further, the Company concluded that it was not “more likely than not” that the fair value of indefinite-lived intangible assets that were qualitatively tested for impairment were less than the carrying amounts. Accordingly, further quantitative testing was not required to be performed. The Company had no indefinite-lived intangible asset impairments in 2022, 2021 or 2020. See Note 8 – Goodwill and Other Intangible Assets for a summary of the Company’s intangible assets. Warranties Warranties are classified as either assurance-type or service-type warranties. A warranty is considered an assurance-type warranty if it provides the customer with assurance that the product will function as intended. A warranty that goes above and beyond ensuring basic functionality is considered a service-type warranty. The Company offers certain limited warranties that are assurance-type warranties and extended service arrangements that are service-type warranties. Assurance-type warranties are not accounted for as separate performance obligations under the revenue model. If a service-type warranty is sold with a product or separately, revenue is recognized over the life of the warranty. Sales of many of the Company’s products include assurance-type warranties based on terms that are generally accepted in the Company’s marketplaces. The Company records provisions for estimated warranty costs, which are included within Cost of sales, at the time of sale based on historical experience. The Company periodically adjusts these provisions to reflect actual experience. Infrequently, a material warranty issue can arise which is beyond the scope of the Company’s historical experience. The Company records costs related to these issues as they become probable and estimable. The Company also sells optional service-type warranty contracts that extend coverage beyond the initial term of the express warranty period. At the time of sale, revenue related to the service-type warranty contract is deferred and typically recognized as revenue on a straight-line basis over the life of the contract. As of December 31, 2022 and 2021, deferred revenue associated with service-type warranty contracts was $4.1 million and $4.0 million, respectively, and was included within Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Costs under service-type warranty contracts are expensed as incurred. Workers’ Compensation and Product Liability Reserves Due to the nature of the Company’s manufacturing and products, the Company is subject to claims for workers’ compensation and product liability in the normal course of business. The Company is self-funded for a portion of these claims. The Company establishes a reserve using a third-party actuary for any known outstanding matters, including a reserve for claims incurred but not yet reported. The amount and timing of cash payments relating to these claims are considered to be reliably determinable given the nature of the claims and historical claim volumes to support the actuarial assumptions and judgments used to derive the expected loss payment patterns. As such, the reserves recorded are discounted using a risk-free rate that matches the average duration of the claims. The Company has not established a reserve for potential losses resulting from the firefighter hearing loss litigation, with the exception of certain estimated losses that have been recognized related to settlement discussions (see Note 13 – Legal Proceedings). If the Company is not successful in its defense after exhausting all appellate options, it would record a charge for such claims, to the extent they exceed insurance recoveries, when the related losses become probable and estimable. Pensions The Company sponsors domestic and foreign defined benefit pension plans. Key assumptions used in the accounting for these employee benefit plans include the discount rate, expected long-term rate of return on plan assets and estimates of future mortality of plan participants. The weighted-average discount rate used to measure pension liabilities and costs is selected using a hypothetical portfolio of high-quality bonds that would provide the necessary cash flow to match the projected benefit payments of the plans. The discount rate represents the rate at which our benefit obligations could effectively be settled as of the year-end measurement date. The weighted-average discount rate used to measure pension liabilities increased from 2021 to 2022. See Note 11 – Pension and Other Post-Employment Plans for further discussion. The expected long-term rate of return on plan assets is based on historical and expected returns for the asset classes in which the plans are invested. The Company references published mortality tables and scales in determining its estimate of future mortality. Revenue Recognition See Note 3 – Revenue Recognition for discussion regarding the Company’s revenue recognition accounting policies. Product Shipping Costs Product shipping costs are expensed as incurred and are included within Cost of sales. Research and Development The Company invests in research to support development of new products and the enhancement of existing products and services. Expenditures for research and development by the Company were $11.5 million in 2022, $11.4 million in 2021 and $12.2 million in 2020, and are included within SEG&A expenses in the Consolidated Statements of Operations. Stock-Based Compensation Plans The Company has various stock-based compensation plans, described more fully in Note 15 – Stock-Based Compensation. Stock-based compensation expense is recorded net of estimated forfeitures in the Company’s Consolidated Statements of Operations. The Company estimates the forfeiture rate based on historical forfeitures of equity awards and adjusts the rate to reflect changes in facts and circumstances, if any. The Company revises its estimated forfeiture rate if actual forfeitures differ from its initial estimates. Income Taxes The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax benefit carryforwards. Deferred tax assets and liabilities at the end of each period are determined using enacted tax rates expected to apply to taxable income in the period in which the deferred tax liability or asset is expected to be settled or realized. A valuation allowance is established or maintained when, based on currently available information and other factors, it is more likely than not that all or a portion of a deferred tax asset will not be realized. The Company files a consolidated U.S. federal income tax return for Federal Signal Corporation and its eligible domestic subsidiaries. The Company’s non-U.S. subsidiaries file income tax returns in their respective local jurisdictions. The Company accounts for taxes on Global Intangible Low-Taxed Income (“GILTI”) as a period expense in the year in which it is incurred. Accounting standards on accounting for uncertainty in income taxes address the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the consolidated financial statements. Under the guidance on accounting for uncertainty in income taxes, the Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company presents interest and penalties related to income tax matters as a component of Income tax expense on the Consolidated Statements of Operations. Litigation Contingencies The Company is subject to various claims, including pending and possible legal actions for product liability and other damages, and other matters arising in the ordinary course of the Company’s business. The Company believes, based on current knowledge and after consultation with counsel, that the outcome of such claims and actions in the aggregate will not have an adverse effect on the Company’s financial position, results of operations or cash flows. However, in the event of unexpected future developments, it is possible that the ultimate resolution of such matters, if unfavorable, could have a material adverse effect on the Company’s results of operations. Professional legal fees are expensed when incurred. The Company accrues for contingent losses when such losses are probable and reasonably estimable. In the event that estimates or assumptions of contingent losses are different from actual results, adjustments are made in subsequent periods to reflect more current information.

Federal Signal Corporation was founded in 1901 and was reincorporated as a Delaware corporation in 1969. References herein to the “Company,” “we,” “our” or “us” refer collectively to Federal Signal Corporation and its subsidiaries.

Products manufactured and services rendered by the Company are divided into two reportable segments: Environmental Solutions Group and Safety and Security Systems Group. The individual operating businesses are organized as such because they share certain characteristics, including technology, marketing, distribution and product application, which create long-term synergies.

The accompanying consolidated financial statements represent the consolidation of Federal Signal Corporation and its subsidiaries and have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) and in accordance with United States (“U.S.”) generally accepted accounting principles (“GAAP”).

In October 2021, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2021-08, Business Combinations (Topic 805), Accounting for Contract Assets and Liabilities from Contracts with Customers, which requires an acquirer to recognize and measure contract assets and liabilities acquired in a business combination in accordance with Revenue from Contracts with Customers (Topic 606) rather than adjust them to fair value at the acquisition date. This ASU, which is applied on a prospective basis, is effective for fiscal years beginning after December 15, 2022, and early adoption is permitted. The Company adopted this ASU effective January 1, 2022, and the application of the amended guidance to the acquisition completed in 2022 did not have a material impact on the Company’s consolidated financial statements.

Assets and liabilities of non-U.S. subsidiaries, other than those whose functional currency is the U.S. dollar, are translated at current exchange rates with the related translation adjustments reported in stockholders’ equity as a component of Accumulated other comprehensive loss. Accounts within the Consolidated Statements of Operations are translated at the average exchange rate during the period. Non-monetary assets and liabilities are translated at historical exchange rates.

The Company incurs foreign currency transaction gains or losses, related to transactions that are denominated in a currency other than the functional currency, which are recognized in the Consolidated Statements of Operations as a component of Other (income) expense, net. For the year ended December 31, 2022, the Company realized foreign currency transaction losses of $0.2 million. For the years ended December 31, 2021 and 2020, the Company realized foreign currency transaction gains of $0.3 million and $0.4 million, respectively.

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities, (ii) the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and (iii) the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

The Company considers all highly liquid investments with a maturity of three months or less, when purchased, to be cash equivalents. The carrying amount of cash and cash equivalents approximates fair value because of the short-term maturity and highly liquid nature of these instruments.

The Company carries accounts receivable at the face amount less an allowance for doubtful accounts for estimated losses as a result of a customer’s inability to make required payments. Management evaluates the aging of the accounts receivable balances, the financial condition of its customers, historical trends and the time outstanding of specific balances to estimate the amount of accounts receivables that may not be collected in the future and records the appropriate provision.

The Company’s inventories are valued at the lower of cost and net realizable value. Cost is determined using the first-in, first-out method. Included in the cost of inventories are raw materials, direct wages and associated production costs.

Properties and equipment are stated at cost, net of accumulated depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets. Useful lives generally range from eight to 40 years for buildings and three to 15 years for machinery and equipment. Leasehold improvements are depreciated over the shorter of the remaining life of the lease or the useful life of the improvement. Depreciation expense is primarily included as a component of Cost of sales on the Consolidated Statements of Operations, with depreciation expense associated with certain assets used for administrative purposes being presented within SEG&A expenses. Depreciation expense, which includes depreciation on rental equipment, was $41.8 million, $39.5 million and $35.2 million for the years ended December 31, 2022, 2021 and 2020, respectively.

The Company enters into lease agreements with customers related to the rental of certain equipment. All of these leasing agreements are classified as operating leases and are for periods generally not to exceed five years. In accounting for these leases, the cost of the equipment purchased or manufactured by the Company is recorded as an asset and is depreciated over its estimated useful life. Rental income is recognized ratably over the term of the underlying leases.

Rental equipment is depreciated to an estimated residual value on a straight-line basis over the estimated useful lives of the assets and is reviewed for potential impairment whenever an event occurs or circumstances change that indicate the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares non-discounted cash flows expected to be generated by that asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on a non-discounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary.

Rental equipment includes certain equipment that is manufactured by the Company and subsequently transferred to the rental fleet, as well as equipment purchased from third-party manufacturers, for the purpose of renting to end-customers. The related cash flow activity associated with these transactions is reflected within operating activities on the Consolidated Statements of Cash Flows.

Goodwill represents the excess of the cost of an acquired business over the amounts assigned to its net assets. Goodwill is not amortized but is tested for impairment at a reporting unit level on an annual basis or more frequently if indicators of impairment exist. The Company performed its annual goodwill impairment test as of October 31, 2022.

In testing the goodwill of its reporting units for potential impairment, the Company applies either a qualitative or quantitative test, in accordance with Accounting Standards Codification (“ASC”) 350, Intangibles – Goodwill and Other.

A qualitative approach may be applied when the Company concludes that it is not “more likely than not” that the fair value of a reporting unit is less than its carrying value. In this situation, the Company would not be required to perform the quantitative impairment test described below.

A quantitative approach is performed by comparing the fair value of a reporting unit with its carrying amount. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired and no impairment charge is required. If the carrying amount of a reporting unit exceeds its fair value, this difference is recorded as an impairment charge not to exceed the carrying amount of goodwill. The Company generally determines the fair value of its reporting units using both the income and market approaches.

Under the income approach, the key assumptions include projected sales, cost of sales, operating expenses and the discount rate. Under the market approach, the Company estimates fair value using marketplace fair value data from within a comparable industry grouping. The results of these two methods are weighted based upon management’s evaluation of the relevance of the two approaches.

In 2022, the Company applied the quantitative approach to assess the goodwill of its reporting units for potential impairment, using a combination of the income and market approaches to determine the fair values of its reporting units. The fair values of the Company’s reporting units exceeded their carrying values by more than 20% and, therefore, no impairment was recognized.

Definite-lived intangible assets are amortized on a straight-line basis over the estimated useful lives and are tested for impairment if indicators exist in a manner similar to that described above for Rental Equipment.

Indefinite-lived intangible assets are tested for impairment on an annual basis at October 31, or more frequently if an event occurs or circumstances change that indicate the fair value of an indefinite-lived intangible asset could be below its carrying amount. In testing the indefinite-lived intangibles assets for potential impairment, the Company applies either a qualitative test, or a quantitative test, in accordance with ASC 350. A qualitative approach may be applied when the Company concludes that it is not “more likely than not” that the fair value of the indefinite-lived intangible assets are less than their carrying value. A quantitative impairment test consists of comparing the fair value of the indefinite-lived intangible asset with its carrying amount. An impairment loss would be recognized for the carrying amount in excess of its fair value.

In 2022, the Company performed a combination of qualitative and quantitative impairment tests over its indefinite-lived intangible assets. The fair value of the indefinite-lived intangible asset that was quantitatively tested for impairment exceeded its carrying value by more than 50%, and, therefore, no impairment was recognized. Further, the Company concluded that it was not “more likely than not” that the fair value of indefinite-lived intangible assets that were qualitatively tested for impairment were less than the carrying amounts. Accordingly, further quantitative testing was not required to be performed.

Warranties are classified as either assurance-type or service-type warranties. A warranty is considered an assurance-type warranty if it provides the customer with assurance that the product will function as intended. A warranty that goes above and beyond ensuring basic functionality is considered a service-type warranty. The Company offers certain limited warranties that are assurance-type warranties and extended service arrangements that are service-type warranties. Assurance-type warranties

are not accounted for as separate performance obligations under the revenue model. If a service-type warranty is sold with a product or separately, revenue is recognized over the life of the warranty.

Sales of many of the Company’s products include assurance-type warranties based on terms that are generally accepted in the Company’s marketplaces. The Company records provisions for estimated warranty costs, which are included within Cost of sales, at the time of sale based on historical experience. The Company periodically adjusts these provisions to reflect actual experience. Infrequently, a material warranty issue can arise which is beyond the scope of the Company’s historical experience. The Company records costs related to these issues as they become probable and estimable.

The Company also sells optional service-type warranty contracts that extend coverage beyond the initial term of the express warranty period. At the time of sale, revenue related to the service-type warranty contract is deferred and typically recognized as revenue on a straight-line basis over the life of the contract. As of December 31, 2022 and 2021, deferred revenue associated with service-type warranty contracts was $4.1 million and $4.0 million, respectively, and was included within Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Costs under service-type warranty contracts are expensed as incurred.

Due to the nature of the Company’s manufacturing and products, the Company is subject to claims for workers’ compensation and product liability in the normal course of business. The Company is self-funded for a portion of these claims. The Company establishes a reserve using a third-party actuary for any known outstanding matters, including a reserve for claims incurred but not yet reported. The amount and timing of cash payments relating to these claims are considered to be reliably determinable given the nature of the claims and historical claim volumes to support the actuarial assumptions and judgments used to derive the expected loss payment patterns. As such, the reserves recorded are discounted using a risk-free rate that matches the average duration of the claims.

The Company has not established a reserve for potential losses resulting from the firefighter hearing loss litigation, with the exception of certain estimated losses that have been recognized related to settlement discussions (see Note 13 – Legal Proceedings). If the Company is not successful in its defense after exhausting all appellate options, it would record a charge for such claims, to the extent they exceed insurance recoveries, when the related losses become probable and estimable.

The Company sponsors domestic and foreign defined benefit pension plans. Key assumptions used in the accounting for these employee benefit plans include the discount rate, expected long-term rate of return on plan assets and estimates of future mortality of plan participants.

The weighted-average discount rate used to measure pension liabilities and costs is selected using a hypothetical portfolio of high-quality bonds that would provide the necessary cash flow to match the projected benefit payments of the plans. The discount rate represents the rate at which our benefit obligations could effectively be settled as of the year-end measurement date. The weighted-average discount rate used to measure pension liabilities increased from 2021 to 2022. See Note 11 – Pension and Other Post-Employment Plans for further discussion.

The expected long-term rate of return on plan assets is based on historical and expected returns for the asset classes in which the plans are invested. The Company references published mortality tables and scales in determining its estimate of future mortality.

The Company invests in research to support development of new products and the enhancement of existing products and services. Expenditures for research and development by the Company were $11.5 million in 2022, $11.4 million in 2021 and $12.2 million in 2020, and are included within SEG&A expenses in the Consolidated Statements of Operations.

The Company has various stock-based compensation plans, described more fully in Note 15 – Stock-Based Compensation. Stock-based compensation expense is recorded net of estimated forfeitures in the Company’s Consolidated Statements of Operations. The Company estimates the forfeiture rate based on historical forfeitures of equity awards and adjusts the rate to reflect changes in facts and circumstances, if any. The Company revises its estimated forfeiture rate if actual forfeitures differ from its initial estimates.

The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax benefit carryforwards. Deferred tax assets and liabilities at the end of each period are determined using enacted tax rates expected to apply to taxable income in the period in which the deferred tax liability or asset is expected to be settled or realized. A valuation allowance is established or maintained when, based on currently available information and other factors, it is more likely than not that all or a portion of a deferred tax asset will not be realized.

The Company files a consolidated U.S. federal income tax return for Federal Signal Corporation and its eligible domestic subsidiaries. The Company’s non-U.S. subsidiaries file income tax returns in their respective local jurisdictions. The Company accounts for taxes on Global Intangible Low-Taxed Income (“GILTI”) as a period expense in the year in which it is incurred.

Accounting standards on accounting for uncertainty in income taxes address the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the consolidated financial statements. Under the guidance on accounting for uncertainty in income taxes, the Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company presents interest and penalties related to income tax matters as a component of Income tax expense on the Consolidated Statements of Operations.

The Company is subject to various claims, including pending and possible legal actions for product liability and other damages, and other matters arising in the ordinary course of the Company’s business. The Company believes, based on current knowledge and after consultation with counsel, that the outcome of such claims and actions in the aggregate will not have an adverse effect on the Company’s financial position, results of operations or cash flows. However, in the event of unexpected future developments, it is possible that the ultimate resolution of such matters, if unfavorable, could have a material adverse effect on the Company’s results of operations. Professional legal fees are expensed when incurred. The Company accrues for contingent losses when such losses are probable and reasonably estimable. In the event that estimates or assumptions of contingent losses are different from actual results, adjustments are made in subsequent periods to reflect more current information.