All states allow drivers to use the left lane (when there is more than one in the same direction) to pass. Most states restrict use of the left lane by slow-moving traffic that is not passing. The table below describes the law in effect in each state.
A few states permit use of the left lane only for passing or turning left. These have "yes" in the "keep right" column. Some states require drivers to move right if they are blocking traffic in the left lane. These have "yield" in the "keep right" column. Most states follow the Uniform Vehicle Code and require drivers to keep right if they are going slower than the normal speed of traffic (regardless of the speed limit; see below). These are listed as "slower". A few states either do not require vehicles to keep right ("no"), or permit vehicles moving at the speed limit to drive in the left lane regardless of traffic conditions ("< SL").
13 AAC 002.50(b)
|Arkansas||Other||Law prohibits obstructing traffic by driving continuously in the left lane.|
|California||Slower||The duty of slower traffic to keep right applies "notwithstanding the prima facie speed limits."|
|Colorado||Slower||42-4-1001(2), 42-4-1103(3), 42-4-1013||
The left lane is reserved for passing where the speed limit is 65 or higher. A state brochure discusses the law.
Passing on right on Interstate prohibited when only two lanes: 14-233(4)
|Florida||Yield||Slower traffic keep right and all traffic yield left lane to traffic approaching from behind.|
|Georgia||Yield||Slower traffic keep right and (since 2014) all traffic yield left lane to traffic approaching from behind.|
Honolulu prohibits driving more than 5 MPH under the limit in the left lane. ROH 15-7.4.
|Illinois||Yes||Keep right except to pass on limited access highways since January 1, 2004.|
As of July 1, 2015 the left lane of a multilane highway is for passing.
|Kansas||Yes||Keep right except to pass on rural roads since July 1, 2009.|
|Kentucky||Yes||Keep right except to pass where speed limit is at least 65.|
|Louisiana||Yes||On multilane highways keep right except to pass and move right if blocking overtaking traffic.|
|Maine||Yes||Keep right except to pass where speed limit is at least 65.|
|Maryland||< SL||Keep right if driving 10 MPH under speed limit, or slower than speed of traffic if conditions require speed below limit|
Passing on right prohibited on undivided two-way road, MGL 89-2.
|Michigan||Maybe||Keep right except to pass except in heavy traffic or on freeways with three or more lanes.|
|Montana||Usually||May also use left lane to allow traffic to merge or "when traveling at a speed greater than the traffic flow."|
|Nevada||Slow||Slow-moving vehicles must move right if "imped[ing] ... movement of traffic." Effective July 1, 2017, a vehicle in the left lane of a controlled access highway must move right when a faster vehicle approaches.|
|New Jersey||Yes||Keep right except to pass. Passing on right prohibited unless vehicles are in "substantially continuous lines." 39:4-85.|
|North Carolina||< SL||Keep right if below speed limit. Some highways are posted "slower traffic keep right."|
|Oklahoma||Slower||One law requires vehicles below the speed limit to keep right. Another requires vehicles below the normal speed of traffic to keep right.|
|Pennsylvania||Usually||75-3313(d), 75-3301(b)||May also use left lane to allow traffic to merge or "when traveling at a speed greater than the traffic flow."|
|Puerto Rico||< SL||Title 9 §5123|
No passing on right on two-way street. 31-15-5.
|South Dakota||No||Only "slow moving vehicles" need to keep right.|
Yield to faster traffic in left lane effective July 1, 2016.
|Must move right to let faster traffic pass.|
Yield left lane to faster traffic on signal. State police say this applies even when faster traffic is speeding.
|Washington||Usually||May also use left lane to allow traffic to merge or "when traveling at a speed greater than the traffic flow."|
Since July 1, 2005, it is illegal to obstruct traffic moving within the speed limit by driving in the left lane for a long time. 31-5-304(c)
The Uniform Vehicle Code states:
Upon all roadways any vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall be driven in the right-hand lane then available for traffic ...
This law refers to the "normal" speed of traffic, not the "legal" speed of traffic. The 60 MPH driver in a 55 MPH zone where everybody else is going 65 MPH must move right. Contrast Alaska's rule, 13 AAC 002.50, allowing vehicles driving at the speed limit to use the left lane, and Colorado rev. stat. 42-4-1103, prohibiting blocking the "normal and reasonable" movement of traffic.
Enforcement is inconsistent. Toledo police used to ticket truck drivers for driving at the 60 MPH speed limit in the left lane. Police looking for criminal activity frequently use the "keep right" law as a pretext to stop a suspicious car. On the other hand, a New York judge announced that he would not convict drivers for blocking speeding traffic, People v. Ilieveski, 175 Misc. 2d 943; 670 N.Y.S.2d 1004 (Monroe County N.Y. 1998).
See also the speed law list.
Do the right thing!: June is lane courtesy month.
This page by John Carr.
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