Insurance adjusters and defense lawyers sometimes treat a posted speed number like automatic proof that a driver was careless: if someone was going over it, they argue fault is obvious; if someone was under it, they argue the driver must have been safe. That shortcut misses what a presumed speed limit really means.

A presumed speed limit is a speed that the law generally treats as reasonable under normal conditions, but not in every situation. Unlike an absolute limit, it creates a rebuttable assumption. Driving faster may be evidence of unsafe driving, but it is not always conclusive by itself. Driving slower does not guarantee safety either. Road design, traffic, visibility, weather, and hazards still matter. On dark rural roads in New Hampshire, for example, a driver can be under the posted speed and still be going too fast for conditions, especially around dusk when moose collisions spike on Routes 3 and 201 and across Coos County.

That distinction matters in a crash claim because insurers often oversimplify speed. They may use a ticket or estimate of speed to push comparative negligence or reduce a settlement. A defense lawyer may also argue that the posted speed creates a built-in excuse.

New Hampshire follows a modified comparative fault rule under RSA 507:7-d. If an injured person is found more than 50% at fault, recovery can be barred. So with a presumed speed limit, the real fight is usually not just the number on the sign, but whether the driver's speed was actually reasonable for the conditions.