How long do tire marks last?
The Takeaway
Tire marks may still be visible 3-6 months after the crash but they’ll be heavily faded and far less helpful to a reconstruction at that point.
Sooner is better when it comes to preserving tire marks (and other scene evidence!).
My advice is generally to target a timeline of days to weeks after the crash to capture most, or all, of the original markings.
Tire marks (aka “skid” marks) have the ability to provide a surprising amount of answers about a crash. Like dragging an eraser across a piece of paper, tire marks quite literally trace a vehicle’s path before, during, and after a crash. They’re good for much more than just tracing paths though. Tire marks can reveal that a driver braked heavily before a crash, help an accident reconstructionist calculate pre-braking speeds and impact speeds, mark the area where the crash occurred, indicate where a vehicle began to lose control and tip over, and can even prove that a particular tire was flat before a crash occurred. But, like all evidence, tire marks are only useful if someone took the time to document and preserve them before they’re gone.
So the question becomes: How long do tire marks last? The answer heavily depends on the road surface (e.g. concrete or asphalt), how much traffic the road sees, and even the weather (e.g. big rainstorms can wash them away). According to one of my favorite resources, Northwestern University Center for Public Safety’s Traffic Crash Investigation textbook:
“If you have a typically dark skid mark on a traffic-polished pavement of a busy street, you may be able to see it [the tire mark] for as long as three months after the event.”
As fresh as they get.
These yaw marks were made just minutes before the photo was taken at a Philadelphia SCCA autocross event. Autocross courses are defined by cones. Competitors battle for the lowest lap time through the course, weaving through the cones. In this case, the driver was carrying too much speed through the turn and their car started to spin - leaving yaw marks as its tires scrubbed the surface of the freshly sealed asphalt.
In my experience, three months is pretty optimistic for finding tire marks. In some cases, I’ve managed to find tire marks months after the crash but they were too faint to show up in photographs and need to be marked with chalk paint for measurements. Of course, the best practice is to document tire marks and other scene evidence as soon as possible. In general, days to several weeks is preferred to ensure:
1) That the marks remain clearly visible, and;
2) To avoid unrelated tire marks at the site from a subsequent crash.
example
I drive on the 611 bypass in Doylestown almost daily. There’s a set of tire marks on the southbound side of the bypass that trace the path of a vehicle that spun around and went off into the treeline to the right of the road. To my amazement, even marks in the travel lane remained visible for months. Through the heavy traffic of 611, rain storms, salt treatments, and a few snow storms - the marks persisted. Most of the marks have faded from sight though and, in their degraded state, they don’t reveal as much, or as useful, information compared to months ago.
I mapped this site two times, six months apart. Both mapping missions were performed by a Mavic 3E with RTK corrections enabled (control points weren’t necessary since we’re only looking at images - not taking measurements). The images below are called ortho projections. Simply put, all of the photos taken by the drone were combined into one big image showing the entire site in high resolution.
Use the slider to compare the “before” map (bright green Summer foliage) to the “after” map taken six months later (brown Winter foliage).
The slider makes the point for me here but I’ll state the obvious anyway - As tire marks fade, valuable insights fade with them.
Take a look at the “after” map. Most of the tire marks are no longer visible and those that are visible are hard to make out at this scale. The “before” map clearly shows that the vehicle began in the left lane (top lane in these photos) and traveled across the right lane, asphalt shoulder, and grass shoulder. The first map also shows tire marks from all four of the vehicle’s tires, making it far easier and more reliable to determine which tire made each mark and fully trace the vehicle’s rotation. In the second map, there are no visible marks in the left lane (though the vehicle still clearly came from that direction), there is only one visible mark in the right lane, two visible marks in the asphalt shoulder, and nothing in the grass median.
Here’s another comparison for good measure. These images are just photographs from each flight (not ortho photos).
Before
After (6 months later)
Final Thoughts
Time is of the essence when it comes to preserving tire marks. The example above demonstrated that some tire marks can remain visible after six months of heavy traffic and bad weather but that’s not common. The coarse concrete surface of the 611 bypass is likely responsible for the longevity of the tire marks in the example (remember, the road surface affects how long the marks last).