<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000002230</issuerCik>
        <issuerName>ADAMS EXPRESS CO</issuerName>
        <issuerTradingSymbol>ADX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001353074</rptOwnerCik>
            <rptOwnerName>Prue Nancy J F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>THE ADAMS EXPRESS COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>7 SAINT PAUL STREET</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2012-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>41.568</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11138.85</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>99.4291</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7152.204</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Issuer's Thrift Plan Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>125.5265</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9138.43</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By PEO Thrift Plan Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-01-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2252</value>
                    <footnoteId id="F6"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.02</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13390.85</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares were acquired in exempt transactions as a result of dividend reinvestment.  The Issuer's stock traded in a range of $9.75 - $11.57 during 2012.</footnote>
        <footnote id="F2">These shares are held by the Issuer's Thrift Plan Trust and represent the undersigned's proportionate beneficial interest in the shares that were acquired by the Trust in 2012 in exempt transactions as a result of periodic contributions made during 2012 and shares acquired by the Trustee through dividend reinvestment in 2012.  The issuer's stock traded in a range of  $9.75 - $11.57 during 2012.</footnote>
        <footnote id="F3">The number of shares reported as held by the Issuer's Thrift Plan Trust represents the undersigned's proportionate beneficial interest in such stock held in the Trust.   Such number is based on information as of December 31, 2012.  This number includes the shares acquired in exempt transactions through periodic contributions made during 2012, shares acquired by the Trustee through dividend reinvestment, and change in the number of shares previously reported due to fluctuations in the market price and interests in the Trust during 2012.  The Issuer's stock traded in a range of $9.75 - $11.57 during 2012.</footnote>
        <footnote id="F4">These shares are held by the Petroleum &amp; Resources Corporation's Thrift Plan Trust and represent the undersigned's proportionate beneficial interest in the shares that were acquired by the Trust in 2012 in exempt transactions as a result of periodic contributions made during 2012 and shares acquired by the Trustee through dividend reinvestment in 2012.  The Issuer's stock traded in a range of $9.75 - $11.57 during 2012.</footnote>
        <footnote id="F5">The number of shares reported as held by the Petroleum &amp; Resources Corporation's Thrift Plan Trust represents the undersigned's proportionate beneficial interest in such stock held in the Trust.  Such number is based on information as of December 31, 2012.  This number includes the shares acquired in exempt transactions through periodic contributions made during 2012, shares acquired by the Trustee through dividend reinvestment, and changes in the number of shares previously reported due to fluctuations in the market price and interests in the Trust during 2012.  The Issuer's stock traded in a range of $9.75 - $11.57 during 2012.</footnote>
        <footnote id="F6">N/A. Restricted Stock Grant.  Shares will vest in 2016.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Nancy J.F. Prue</signatureName>
        <signatureDate>2013-01-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
