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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-03-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000049615</issuerCik>
        <issuerName>ID SYSTEMS INC</issuerName>
        <issuerTradingSymbol>IDSY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001107329</rptOwnerCik>
            <rptOwnerName>EHRMAN KENNETH S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O I.D. SYSTEMS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>123 TICE BOULEVARD</rptOwnerStreet2>
            <rptOwnerCity>WOODCLIFF LAKE</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07677</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2012-03-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8447</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.92</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>548069</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Kenneth S. Ehrman (the &quot;Reporting Person&quot;) transferred and sold these 8,447 shares (the &quot;Shares&quot;) of common stock, par value $0.01 per share (&quot;Common Stock&quot;), of I.D. Systems, Inc. (the &quot;Company&quot;) to a family member in consideration of, and in partial repayment for, a personal loan to the Reporting Person.  The deemed purchase price for each Share was equal to the closing bid price of the Common Stock on the trade date of March 15, 2012.</footnote>
        <footnote id="F2">This number also includes (i) 17,655 restricted shares of Common Stock which vest on June 29, 2012, provided that the Reporting Person is employed by the Company on such date, (ii) 21,930 restricted shares of Common Stock which vest on February 5, 2013, provided that the Reporting Person is employed by the Company on such date, (iii) 8,020 restricted shares of Common Stock which vest on March 30, 2014, provided that the Reporting Person is employed by the Company on such date, (iv) 49,000 shares of Common Stock held by the Reporting Person's wife's IRA account, and (v) 16,500 shares of Common Stock held by the Reporting Person's 401(k) account.</footnote>
        <footnote id="F3">In reports previously filed by the Reporting Person under Section 16 of the Securities Exchange Act of 1934, as amended, with respect to the Company's Common Stock, this number also had included the number of stock options held by the Reporting Person that were currently exercisable or which would become exercisable within 60 days of the date of the transaction requiring such report.  Commencing with this report, the number of stock options held by the Reporting Person has now been properly excluded from the total number of non-derivative securities reported in Table I.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: /s/ Kenneth S. Ehrman</signatureName>
        <signatureDate>2012-03-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
