Crashes are not spread evenly across a city. They cluster — and they cluster hard, at a relatively small number of intersections that account for a wildly disproportionate share of collisions. Salt Lake County is a clear example.
Why intersections concentrate risk
An intersection is the only place on a road network where traffic paths legally cross. Everywhere else, vehicles are traveling roughly parallel; here they are at right angles, turning across each other, with pedestrians crossing and sightlines blocked by queued cars. Add a signal phase that has to be obeyed exactly and you have a small area doing a lot of work.
The intersections that show up repeatedly in our footage tend to share several features:
- High volume in both directions — two busy arterials crossing, not a busy road crossing a quiet one
- Unprotected left turns — permissive greens where drivers judge gaps themselves
- Wide crossings — six or more lanes, so clearing takes longer than drivers expect
- Speed differential — a 45 mph arterial meeting a 30 mph street; the fast approach dominates the outcome
- Commercial driveways close to the corner — turns in and out immediately before or after the signal
- Sun angle — long east-west arterials with brutal glare at commute times
The same corner produces the same crash over and over, because the geometry has not changed since the last one.
Where they concentrate in the valley
Across Salt Lake County, the pattern follows the major arterial grid. State Street, Redwood Road, 5600 West and the numbered east-west corridors — 3300 South, 4500 South, 5400 South, 9000 South — are where volume, width and speed all coincide. Crossings between two of those roads carry substantially more risk than either road alone. The I-15 and I-215 interchange approaches add merging traffic to the mix.
Working from real data. We hold a mirror of state crash records alongside our own detections, and we are compiling a verified ranked list of the county's highest-collision intersections from it rather than repeating figures from elsewhere. When it is published it will link from here.
How to drive them
- Pause on green. A one-second look left before you enter is the single highest-value habit at a large intersection.
- Do not take a marginal left. Wait the cycle. The queue behind you is not your problem.
- Treat a fresh yellow as a stop unless stopping is unsafe. Most red-light crashes start as a yellow-light decision.
- Leave a car-length of space at the front of a queue so you have somewhere to go if you are hit from behind.
- Watch the driveways immediately past the signal — turning traffic there behaves as if the intersection has ended, and it has not.
If it already happened
We have 187 cameras across Utah, heavily weighted toward exactly these corridors. If you were hit at one of them, there is a real chance we have it — with the signal timing and both approach speeds already worked out.