“You have the right to remain silent.” That line from countless TV and movie crime dramas is so ingrained in our heads that more Canadians on a per capita basis can recite the Miranda rights of the U.S. than its own citizens. But what’s this got to do with autos? For the overwhelming majority of Canadian drivers, if a serious collision occurs, our vehicles can rat us out faster than a sweating street thug under the hot lights in a police interrogation room.

Event Data Recorders, or EDRs for short, exist in about 96 per cent of vehicles on the road according to the last study done by the U.S. National Highway Traffic Safety Administration (NHTSA) in 2013. They primarily exist as software written into airbag computers that continually record vehicle operating data in an over-writing loop process.

When a collision sets off any of the airbags, this software will lock the previous five to 30 seconds of data onto the computer, where it can be retrieved through the vehicle’s diagnostic link connector located under the left side of the dash. This software monitors such things as vehicle speed, acceleration, braking, steering wheel angle, and whether or not the seatbelts were in use, or even if there was a passenger in the right front seat. The primary purpose for their design was to enable vehicle manufacturers to complete post-collision analyses to determine if passenger protection systems were living up to their purpose, but police investigators now find they can provide great and irrefutable evidence in criminal proceedings.

The NHTSA, until recently, was urging U.S. lawmakers to make such devices/software mandatory on all vehicles sold in that country, but it has apparently dropped its plans for regulations due to the large majority of vehicles now using them. They are still trying to convince automakers to standardize the information collected and recorded, including an increased recording duration. The onboard computers require specialized equipment to retrieve the recordings, but this is readily available to private groups and individuals as well as police and insurance authorities.

In the event of a serious collision involving injuries or death, police have the option of asking for voluntary release of this data or seeking a court order to force compliance. In some jurisdictions in the U.S., police have retrieved this data without the vehicle owner’s permission. In cases where other evidence, including eye witnesses, may be inconclusive, EDRs can help seal a criminal case.

Currently, 15 states in the U.S. have legislation on the books requiring automakers to notify their customers of the existence of EDRs in their products, detailing who can see the information they produce and under what circumstances. You’ll find it in that often-unread tome called an owner’s manual. If you want to find out if your ride has EDR capability, log onto harristechnical.com. This collision investigation company has a handy reference list (1994–2014 model years) accessible from its website home page.

In any circumstance where an individual is facing serious criminal prosecution, few would argue that they should proceed alone, but rather with the presence and advice of an experienced lawyer. The same advice holds true when dealing with the silent witness of a vehicle EDR. But at the roadside in the aftermath of a major collision, it’s often difficult to work through emotional tolls and unfamiliar processes; however, securing your property, including whatever data your vehicle has recorded, should be considered.

Most insurance documents in your glovebox contain advice on what to do in the case of a collision, and specifically warn against admitting liability until all the facts are known. Don’t let your vehicle make statements on your behalf without your consent. Ensure you know exactly where your vehicle will be taken if it has to be towed away; find out if the impound facility that will receive it has a written policy on privacy protection. Commercial enterprises in Canada are required to have such policies under the Personal Information Protection and Electronics Documents Act.