Question 1

What is the Federal Bridge Formula B?

Accepted Answer

The Federal Bridge Formula B W = 500 * [LN/(N-1) + 12N + 36] determines the maximum legal weight carried on any consecutive group of truck axles based on axle count (N) and distance in feet (L).

Question 2

What is the statutory limit for a standard tandem axle group?

Accepted Answer

Under federal law (23 CFR § 658.17), a standard tandem axle group spaced between 40 inches and 96 inches is capped at 34,000 lbs.