What Illinois law says about the left lane

The rule is in Section 11-701 of the Illinois Vehicle Code, titled Drive on right side of roadway - exceptions. Subsection (d) says that upon an Interstate highway or fully access controlled freeway, a vehicle may not be driven in the left lane, except when overtaking and passing another vehicle.

In other words, on roads like an interstate, the left lane is for passing. Once you have passed and are safely clear of the vehicle you overtook, move back to the right. Section 11-703 says a driver overtaking another vehicle going the same direction shall pass to the left at a safe distance and shall not drive back to the right side of the roadway until safely clear of the overtaken vehicle.

From the Illinois Vehicle Code, 625 ILCS 5, Chapter 11, on the Illinois General Assembly website, read November 9, 2026. This is a plain-language summary, not legal advice.

The eight exceptions

Subsection (e) of Section 11-701 says the left-lane rule does not apply:

For more on moving over for stopped emergency and disabled vehicles, see our guide to the Illinois Move Over Law (Scott's Law).

From the Illinois Vehicle Code, 625 ILCS 5, Chapter 11, on the Illinois General Assembly website, read November 9, 2026. This is a plain-language summary, not legal advice.

Other Illinois lane rules

• Two-lane, two-way roads: under Section 11-701(b), a vehicle shall be driven in the right-hand lane available for traffic, or as close as practicable to the right-hand curb or edge of the roadway, except when overtaking and passing another vehicle going the same direction, or when preparing for a left turn at an intersection or into a private road or driveway.
• Four or more lanes, two-way traffic: under Section 11-701(c), no vehicle shall be driven to the left of the center line, except where official traffic-control devices designate lanes left of center for traffic not otherwise permitted to use them, or around an obstruction. This does not prohibit crossing the center line to turn left into or from an alley, private road or driveway.
• Lane signs: Section 11-709(c) says drivers shall obey official traffic control devices directing specific traffic to use a designated lane. On multi-lane controlled access highways with 3 or more lanes in one direction, or any multi-laned highway with 2 or more lanes in one direction, the Department may designate lanes for different types of motor vehicles, and drivers must obey that lane designation signing except when they need a different lane to turn.
• Driving too slowly: Section 11-606(a) says no person shall drive a motor vehicle at such a slow speed as to impede or block the normal and reasonable movement of traffic, except when reduced speed is necessary for safe operation or to comply with law. For posted limits, see Illinois speed limits.

From the Illinois Vehicle Code, 625 ILCS 5, Chapter 11, on the Illinois General Assembly website, read November 9, 2026. This is a plain-language summary, not legal advice.

Keep right and passing signs

These are regulatory signs in the MUTCD, the federal standard for signs, signals and markings. Regulatory signs tell road users about selected traffic laws or regulations. They are rectangular unless the MUTCD says otherwise, and in its color code black and white both mean regulation. For other sign colors and shapes, see our guide to road sign shapes and colors.

From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 1D.05, 2B.01, 2B.02, 2B.38, 2B.40 and 2B.43 and Figure 2B-10, read November 9, 2026.

Where you will see them

• KEEP RIGHT EXCEPT TO PASS: if used, it should be installed at or just beyond the beginning of a two-lane section of roadway, and at selected locations along two-lane roadways where additional emphasis is needed.
• SLOWER TRAFFIC KEEP RIGHT and TRUCKS USE RIGHT LANE: if used, they should be installed at or just beyond the beginning of a multi-lane section, or at the beginning of an extra lane provided for trucks and other slow-moving traffic, and at selected locations where some drivers tend to drive in the left-hand lane or lanes below the normal speed of traffic.
• Interchanges: the MUTCD says the SLOWER TRAFFIC KEEP RIGHT and TRUCKS USE RIGHT LANE signs should not be used on the approach to an interchange, through an interchange area where traffic is entering or exiting, or along deceleration or acceleration lanes.
• Extra truck lanes: where an extra lane is provided for trucks and other slow-moving traffic, a Lane Ends sign should be installed in advance of the point where it ends. See our guide to merge and lane ends signs.

From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Section 2B.38, read November 9, 2026.

Related passing signs

• DO NOT PASS (R4-1): may be used in addition to pavement markings to emphasize the restriction on passing, at the start of and at intervals within a zone where sight distance is restricted or other conditions make passing inappropriate.
• PASS WITH CARE (R4-2): should be installed at the downstream end of a no-passing zone if a Do Not Pass sign was installed at the upstream end. For the yellow pennant and the lines that mark these zones, see our guide to no passing zone signs.
• Slow vehicle turn-outs (R4-12, R4-13, R4-14): on two-lane highways where passing is difficult, a turn-out area is sometimes provided so a group of faster vehicles can pass a slow-moving vehicle. The R4-12 sign reads SLOW VEHICLES WITH XX OR MORE FOLLOWING VEHICLES MUST USE TURN-OUT and may be installed ahead of a turn-out to tell drivers who have built up that many following vehicles that State traffic law requires them to use the turn-out; if it is installed, a SLOW VEHICLES MUST TURN OUT (R4-14) sign with an arrow is required at the entry point of the turn-out.

From the Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition with Revision 1, Sections 2B.36, 2B.37 and 2B.42, read November 9, 2026.

Using the left lane well

Our advice: on the interstate, pass with purpose and then signal and move back right once you can see the vehicle you passed in your mirror and you are safely clear. If a faster vehicle comes up behind you in the left lane, finish your pass and move over rather than speeding up to hold the lane. When you are towing a trailer or driving a loaded truck, plan passes early, because it takes longer to get past and back into the right lane.

Paragraphs marked as our advice are our own guidance, not MUTCD or statute text.

Keep your vehicle ready for the road

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Ford of Peoria service hours

From Ford of Peoria's website, November 9, 2026. Holiday hours can differ.