Segment Information (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments			2
Revenue	$ 3,689	$ 4,049	$ 11,286	$ 10,952
Gross profit	3,176	3,306	8,797	9,061
Amortization of intangible assets	149	149	448	380
Intangible assets	3,911	3,239	3,911	3,239
Intersection [Member]
Segment Reporting Information [Line Items]
Revenue	2,789	2,599	7,373	7,858
Gross profit	2,555	2,386	6,586	7,168
Amortization of intangible assets	92	91	275	275
Intangible assets	1,835	2,202	1,835	2,202
Highway [Member]
Segment Reporting Information [Line Items]
Revenue	900	1,450	3,913	3,094
Gross profit	621	920	2,211	1,893
Amortization of intangible assets	57	58	173	105
Intangible assets	$ 2,076	$ 1,037	$ 2,076	$ 1,037

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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