Safety

Safer for everyone on the road, starting with drivers

Safety is the reason for this project. Most of the crashes a road diet prevents are between cars: rear-ends, sideswipes and left turns. The people walking and biking to our schools benefit too.

Why this road crashes

Boston Post Road squeezes four travel lanes into a width that barely fits them. Each lane is about 9.5 feet wide, where the standard is 11. That leaves little room for error.

Then add the turns. Driveways, side streets and parking spaces line the corridor, and every driver waiting to turn left stops in a travel lane. The drivers behind brake hard or swerve into the next lane, and on 9.5-foot lanes both go wrong often.

How a road diet prevents each kind of crash

The road diet targets the crash types FHWA reports falling most after four-lane roads become three. Pick one to see how it happens today and how the new layout changes it. Fire trucks and ambulances have their own page.

What the research says

19–47%

fewer crashes overall

After four-lane roads were converted to three, in studies the Federal Highway Administration cites.

Proven

safety countermeasure

FHWA's label for safety treatments with a proven record of reducing crashes.

3 kinds

of crash drop most

Rear-end, left-turn and sideswipe: the exact crashes that four narrow lanes and constant left turns produce.

Sources
  1. FHWA, Road Diet Informational Guide, ch. 2
    Four-to-three conversions: 19–47% fewer total crashes, including rear-end, left-turn and sideswipe.
    highways.dot.gov