Idaho Truck Following Distance
No fixed feet. Idaho's only truck-specific line covers a rig towing another vehicle behind another towing rig outside town: leave enough room for a passing car to merge back in (Idaho Code 49-638(2)). It never stops you from passing. Behind a car, in traffic, or in town the rule is reasonable and prudent (49-638(1)). That's the CDL seconds gap, roughly 7 seconds at highway speed. Tailgating is a $50 infraction.
How much room Idaho makes you keep
No fixed feet. Idaho's only truck-specific line covers a rig towing another vehicle behind another towing rig outside town: leave enough room for a passing car to merge back in (Idaho Code 49-638(2)). It never stops you from passing. Behind a car, in traffic, or in town the rule is reasonable and prudent (49-638(1)). That's the CDL seconds gap, roughly 7 seconds at highway speed. Tailgating is a $50 infraction.
The required distance
- Rule: Gap between trucks
- Gap: No fixed feet — a combination towing another vehicle must leave room for a passing car to merge; behind anyone else, reasonable and prudent
- Fine: Infraction, about $50 base plus court costs (Idaho Code 49-638)
Idaho Following Distance FAQ
How much following distance must a truck keep in Idaho?
What is the required gap in Idaho?
What is the following-too-closely fine in Idaho?
Reference information for planning, not legal advice. Traffic laws change and this can be out of date, so always confirm the current statute and obey posted signs before you rely on it. Last reviewed July 2026. Source: https://legislature.idaho.gov/statutesrules/idstat/title49/t49ch6/sect49-638/. See our Terms & Disclaimer.
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