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What is an ignition interlock device?

ignition interlock device

An ignition interlock device (I/I) is a small device that is connected to a vehicle’s ignition system, preventing the car from starting if alcohol is present in a breath sample given by the driver.

This device may be required to regain driving privileges after a DWI charge and ensures that you’re able to operate a vehicle during a probationary period in a legal way.

In Texas, an ignition interlock device can be installed for those facing a first or subsequent conviction where the blood alcohol concentration (BAC) level exceeds the .08 level. This allows those charged by DWI to retain their driving privileges during their period of license suspension. However, someone facing a charge can opt to go for a hard suspension instead to prevent the device from being installed in their vehicle.

How does an ignition interlock device work?

The device consists of two parts: a handset that is mounted to the dashboard and a relay module that connects to your vehicle’s wiring. Both are connected through a coiled cable that facilitates use while operating the vehicle.

This device is mounted on the dashboard where a breath sample is collected into a fuel cell chamber. Upon breathing into the mouthpiece, the alcohol level in the breath is measured through a reaction across the surface on the fuel cells. This produces an electrical current which determines if the car is permitted to start or continue operation based on the permissible level of BAC set on the device.

The device is not able to turn off your car due to safety precautions.

How do I use an ignition interlock device?

The IID is operated by holding the device in one hand where they will be then prompted to blow into the mouth piece. If no alcohol is detected in the breath sample, the vehicle is allowed to start. However, if an alcohol level above the set point on the device is found, it will not allow the vehicle to start.

Most devices feature a rolling retest feature which prompts the driver to blow into the device while the vehicle is in use, often within 15 minutes of starting it. This is done to ensure that the driver is still able to drive while confirming that they did not have someone else blow into the device for them.

If no alcohol is detected or the driver’s BAC is lower than the set point, the vehicle continues without interruption. However, if the rolling retest is failed after several attempts the car might be locked out which results in the lights of the vehicle beginning to flash and the horn honking until the vehicle is turned off.

In certain states, a camera might be required to be used alongside the ignition interlock device to ensure that the driver is the one who is providing the breath sample.

How much does an interlock device cost in San Antonio?

Most interlock device installations cost around $70 to $150. However, there are also additional costs for the device that are not included. This includes the calibration fee, monthly rental fees, maintenance fees, as well as de-installation fees. Calibration fees have been reported to be at around $60 to $80, however the price could be much higher depending on the model used.

Along with these costs, there are also additional fees added for supervision and for license restrictions.

In the Bexar county, there is a $10.00 monthly supervision fee and a device installation is required by the given date upon release with a proof of installation.

The cost for adding an interlock restriction to your license is $10, with suspensions ranging from 90 days to 2 years.

If you don’t currently own a vehicle, you must complete an affidavit of non-ownership that carries with it a fee of $10.00. However, this will often result in other supervision methods which include SCRAM, Soberlink, GPS, IN HOM, ELM, and Antabuse which range from $69.00 up to $357.00 monthly.

Facing a DWI charge?

The DWI attorneys from the Law Offices of Ramos & Del Cueto are ready to help you in your case.

Whether you are facing an ignition interlock violation or a DWI charge, our team has years of experience handling cases related to drunk driving and criminal defense. We ensure that our clients get the justice that they deserve and work hard to protect their innocence.

Let our team put their experience to work for you.