Some equipment rules apply to every vehicle whether or not it needs an inspection: plates, plate lights, loads, towing and window tint. In the St. Louis area, vehicles also need emissions inspections.
Know the rule
License plates must be securely fastened, fully visible and clean; frames must not cover any part. With two plates, put one on the front and one on the back. Trailers and motorcycles get one plate, on the back.
Handbook p. 87 ↗Know the rule
Trucks licensed over 12,000 pounds get one plate, which goes on the front. A second plate must be specifically requested and goes on the rear.
Handbook p. 87 ↗Equipment rules
| Item | Rule |
|---|---|
| License plate light | White light; plate visible from 50 feet |
| Load overhang over 5 ft | Day: red flag 16 in. square; night: red light |
| Towline | Vehicles within 15 ft; both lit at night |
| Slow moving vehicle sign | Vehicles at 25 mph or slower |
| Studded snow tires | Only November 1 to April 1 |
| Front door window tint | No more than 65% light blockage |
Know the rule
The slow moving vehicle sign is required from sunset to ½ hour before sunrise. It goes on the rear, near the middle, four feet or more above the road, and must be clean and reflective.
Handbook p. 87 ↗Know the rule
An overhang's red light, and lights on both vehicles when towing, are required from ½ hour after sunset until ½ hour before sunrise. Tint is allowed on side and rear windows.
Handbook p. 87 ↗Know the rule
Residents of St. Louis City and St. Louis, St. Charles, Franklin and Jefferson counties also need emissions inspections. They're every two years, following the same even/odd model year pattern.
Handbook p. 87 ↗Know the rule
All vehicles must be emissions inspected at the time of sale regardless of model year (unless exempt). New vehicles and first retail sales during the model year and the next are exempt if the odometer reads under 6,000 miles.
Handbook p. 88 ↗Exempt from emissions inspection:
- New, never-titled vehicles in their model year and the next, with no change in ownership
- Gasoline vehicles 1995 and older; diesel vehicles 1996 and older
- Vehicles with a GVWR over 8,500 pounds
- New vehicles for four years after model year, with under 40,000 miles at the first inspection
- Vehicles driven under 12,000 miles between biennial safety inspections
- Vehicles powered by fuels other than gasoline, ethanol or diesel
- Historic, school bus, shuttle bus, motorcycle, motortricycle or street rod plates
- Gasoline-powered low speed vehicles, in Franklin County only
- Registered in the area but based and operated outside it for 24 consecutive months
Put it into practice
You're towing a friend's car at dusk. Keep the towline short enough that the vehicles stay within 15 feet of each other, and once it's ½ hour after sunset, both vehicles must have their lights on.