Table 1.

Measures of Non-Compliance with Interlock Requirements

Measures	Definitions of Measures of Non-Compliance
Initial Fails ≥.025 5 minutes	Initial breath test failure BAC≥.025 per 1,000 engine starts 5 or more minutes apart
Initial Fails ≥.025 60 minutes	Initial breath test failure BAC≥.025 per 1,000 engine starts 60 or more minutes apart
Initial Fails ≥.04 5 minutes	Initial breath test failure BAC≥.04 per 1,000 engine starts 5 or more minutes apart
Initial Fails ≥.04 60 minutes	Initial breath test failure BAC≥.04 per 1,000 engine starts 60 or more minutes apart
Initial Fails ≥.08 5 minutes	Initial breath test failure BAC≥.08 per 1,000 engine starts 5 or more minutes apart
Initial Fails ≥.08 60 minutes	Initial breath test failure BAC≥.08 per 1,000 engine starts 60 or more minutes apart
Total Fails Weighted	Weighted average of failure rates = (.025 + 2 × .04 + 4 × .08)/7
Total Non-compliance	Weighted sum of non-compliance rates = (7 × total failures + disconnects + retest refusals + retest failures + startup violations).
Disconnects	Disconnecting power to the hand set or ignition interlock per 1,000 engine starts
Retest Refusal	Rolling retest was requested but no breath blow was provided per 1,000 engine starts
Retest Failure	Rolling retest breath blow provided was ≥ .025 per 1,000 engine starts
Startup Violationa	Starting the vehicle by by-passing the ignition per 1,000 engine starts*
Initial Passes Per Month	Average number of initial breath tests passed per month

^aVendor manuals provided to drivers assigned to ignition interlocks offer several different interpretations of “start-up violations.” In some cases, the “violation” may be inadvertent rather than deliberate, when the driver follows incorrect procedures or there is a hardware problem. However, the term “start-up violation” usually means that the driver has circumvented the proper operation of the interlock system either by providing a jumper wire across the interlock relay or by providing battery power directly to the vehicle’s starter.