Stop bars get cited in liability claims at signalized and stop-controlled intersections more than any other marking, because their placement decides where a stopped vehicle's bumper actually ends up relative to the crosswalk and cross-traffic lane. MUTCD Section 3B.16 sets the dimensions, placement, and color. At high-AADT intersections, paint repaints every 1 to 3 years aren't a workable plan, so thermoplastic is what we run. Below is the spec plus how the install actually goes.
Direct answer: A thermoplastic stop bar under MUTCD Section 3B.16 is a solid white transverse line, 12 to 24 inches wide, placed perpendicular to the lane direction, set 4 feet in advance of the nearest crosswalk line or 4 feet upstream of the first conflict point. Hot-applied thermoplastic per AASHTO M249 at 90 to 125 mil with M247 Type I glass beads is the typical material specification.
What Are the MUTCD Dimensions for a Stop Bar?
MUTCD Section 3B.16 states that stop lines should be solid white lines extending across approach lanes, with a width of 12 to 24 inches. The line is placed perpendicular to the centerline of the approach. Where used with a marked crosswalk, the stop line is set 4 feet in advance of the nearest crosswalk line. Where there is no crosswalk, the stop line is set at the desired stopping point but not more than 30 feet, nor less than 4 feet, from the nearest edge of the intersecting traveled way.
These dimensions apply whether the marking is paint, hot-applied thermoplastic, preformed thermoplastic, or methyl methacrylate (MMA). The material does not change the dimensional spec, only the durability and the install procedure.
Why Choose Thermoplastic for Stop Bars Specifically?
Stop bars sit at the highest-wear point of any pavement marking on a roadway. Every approaching vehicle decelerates over the line, and a meaningful percentage of vehicles stop their tires directly on the line. Hot-applied thermoplastic at 90 to 125 mil resists this wear far better than 6-mil dry traffic paint.
ODOT and most Oregon municipalities specify thermoplastic for stop bars on routes inside the National Highway System or on routes feeding signalized intersections with above-2,500 AADT. The Federal Highway Administration's pavement marking management research links thermoplastic stop-bar service life to traffic count, with extruded 125-mil bars achieving 6 to 10 years on moderate-AADT intersections.
What Materials Options Are Allowed?
Three thermoplastic delivery formats are common for stop bars:
Hot-applied extruded thermoplastic:
- Ribbon-extrusion through a hand-liner or ride-on melter
- Mil thickness 90 to 125 standard
- Best for stop bars on long-run jobs (alongside lane line work)
Preformed thermoplastic templates:
- Pre-cut sheet applied with a propane infrared heater
- Mil thickness typically 125 to 150 (manufacturers' standard sheet thicknesses)
- Best for stop bars on intersection-only jobs without surrounding line work
- Roughly 90 seconds per stop bar to apply once the substrate is prepped
Sprayed thermoplastic:
- Less common for stop bars because the line edges are softer
- Mil thickness 60 to 90
- Used when the surrounding lane work is also sprayed for visual continuity
Our extruded vs preformed thermoplastic decision guide covers those trade-offs at job-planning time.
How Is a Thermoplastic Stop Bar Installed?
The full thermoplastic application sequence is in our how to apply thermoplastic guide. For a stop bar specifically:
- Verify substrate temperature is 50 degrees F or higher with dry pavement and dewpoint margin of 5 degrees F.
- Sweep and grind the substrate. For aged asphalt, prime with a low-VOC concrete or asphalt primer per the manufacturer's instructions.
- Lay out the stop-bar position with chalk or a pre-marked template, set 4 feet in advance of the crosswalk per MUTCD Section 3B.16.
- For preformed: position the template, apply the propane IR heater for 90 seconds (or per the SKU's heating instructions), and roll for substrate adhesion. For extruded: heat the resin to 410 degrees F and ribbon-extrude with the hand-liner across the bar dimension.
- Drop AASHTO M247 Type I glass beads at 8 to 12 pounds per 100 square feet on the still-warm thermoplastic.
- Allow cooling to ambient temperature (typically 5 to 15 minutes) before opening to traffic.
What Common Mistakes Should Be Avoided?
The most common stop-bar errors are positional. A stop bar set fewer than 4 feet from the crosswalk creates an ADA conflict because pedestrians on the crosswalk are exposed to vehicle bumpers. A stop bar set more than 30 feet from the intersecting traveled way violates MUTCD 3B.16's outer limit. Both create rebuild requirements after city or ODOT inspection.
Material errors come second. Using paint where the spec called for thermoplastic, dropping insufficient bead, or applying onto a wet or below-50-degrees-F substrate are the three failures Cojo most often replaces on rebid jobs.
How Does a Thermoplastic Stop Bar Compare to Painted?
For the service-side painted stop-bar context (and mixed paint-plus-thermoplastic jobs), our crosswalk stop bar painting guide walks it through. The material trade-off in short: paint runs roughly one-third the install price of thermoplastic but needs a repaint every 1 to 3 years at typical signalized-intersection AADT, while thermoplastic holds 6 to 10 years extruded or 5 to 7 years preformed.
What Does Thermoplastic Stop Bar Installation Cost?
Industry Baseline Range
| Format | Installed price per stop bar |
|---|---|
| Sprayed 90-mil thermoplastic | $200 to $450 per bar |
| Extruded 125-mil thermoplastic | $250 to $700 per bar |
| Preformed thermoplastic template | $300 to $750 per bar |
Current Market Reality
Stop-bar installs on intersection-only mobilizations cost more per bar than the same work added to a larger linear job because crew mobilization and traffic-control plan costs are amortized over fewer line items. Combining stop-bar work with adjacent crosswalk, ISA symbol, or lane-line work is the most common way to keep per-unit pricing inside the baseline range.
Recent Cojo Stop Bar Install
In April 2026 we put eight 24-inch preformed thermoplastic stop bars down at a four-leg signalized intersection retrofit in Salem, paired with two continental crosswalks and a pair of ISA symbols. Substrate ran 58 to 64 degrees F across the install window. Bead drop hit 10 pounds per 100 square feet on AASHTO M247 Type I beads. Opening-day retroreflectivity met ODOT's 250 mcd/m^2/lx target. If you're in Salem, our Salem thermoplastic install page covers the area.
Frequently Asked Questions
What is the minimum stop bar width under MUTCD? 12 inches. The maximum is 24 inches. Most Oregon municipalities specify 18 or 24 inches for arterial intersections to improve visibility for high-cab vehicles.
Where does the stop bar go relative to the crosswalk? 4 feet in advance of the nearest crosswalk line per MUTCD Section 3B.16. Where there is no crosswalk, the stop bar is placed at the desired stopping point but not more than 30 feet nor less than 4 feet from the nearest edge of the intersecting traveled way.
Can a stop bar be yellow? No. MUTCD Section 3B.16 specifies the stop line as a solid white line. Yellow is reserved for centerline and lane-direction markings.
How long does a thermoplastic stop bar last in Oregon? Five to ten years on extruded 125-mil bars, four to seven years on preformed bars, depending on intersection AADT and substrate condition. Sprayed 90-mil bars typically hold 3 to 5 years.
Does the stop bar need to span all approach lanes? Yes. MUTCD specifies that the stop line extends across approach lanes. A multi-lane approach gets a continuous stop line spanning all lanes, not separate per-lane bars.