Regulatory sign · MUTCD R2-1
Speed Limit
The number is the maximum legal speed in miles per hour under ideal conditions. It is a ceiling, not a target.
- Shape
- Vertical rectangle
- Color
- White background, black letters and numbers
What to do
Do not exceed the posted number. Drive slower when rain, snow, fog, darkness, heavy traffic or road work make it unsafe to go that fast. If a minimum speed is also posted, stay above it unless conditions make that unsafe.
Where you see it
On the right side of the road where a speed limit begins or changes, and repeated at intervals.
Test trap
The posted limit is not always a safe speed; you can be ticketed for driving 55 in a 55 zone if conditions make it unsafe. White speed limit signs are regulatory; a yellow or orange sign with a number is only an advisory speed for a curve or ramp.
Memory tip: White rectangle with a number = the law; yellow with a number = advice for a curve.
Practice question
A white sign reading SPEED LIMIT 55 means:
- 55 mph is the maximum legal speed under ideal conditions
- 55 mph is the minimum speed
- 55 mph is only a suggestion
- You must drive exactly 55 mph
Answer: A. It is the highest legal speed in good conditions; slow down for rain, traffic or darkness.
MUTCD sign meanings (as taught in state driver handbooks)