Construction signs are the orange work zone signs from MUTCD Part 6 that warn drivers about road work, closed lanes, flaggers and detours before they reach them. Every sign in this category is printed on our .080" reflective aluminum, the same orange diamond you drive past on every highway project.
What Is a Construction Sign?
A construction sign is a temporary traffic control sign, black legend on an orange background, used to move traffic safely past road work. The orange color is reserved by the MUTCD for work zones, so a driver knows at a glance that the condition is temporary and that people may be working close to the lane. Most of the signs in this category are the W20 and W21 diamond warning series. The category also includes the rectangular Road Closed regulatory signs, the orange Detour guide signs and the plaques that mount under a diamond.
Work zone signs are used by highway contractors, utility crews, paving companies, municipalities and property owners. They go up for a few hours around a pothole repair or for months on a highway reconstruction. Either way, the MUTCD requires the same thing: every sign must be in new or like-new condition each time it is deployed.
Which Construction Sign Do You Need?
Start with the situation a driver will meet, then pick the sign that names it. Each row below links to the sub-category that holds every size, distance and left/right version of that sign.
Scroll sideways to view the full table on smaller screens.
| Situation | Signs to use | MUTCD codes |
|---|---|---|
| Work is starting ahead and drivers need a first warning | Road Work Ahead Signs, with 500 ft to 1 mile distance versions | W20-1, W20-1 with distance |
| Workers are on or next to the road | Workers Ahead Signs and Utility Work Signs | W21-1, W21-1B, W21-7 |
| A flagger is controlling traffic | Flagger Signs | W20-7, W20-7B |
| One or more lanes are closing | Lane Closed Signs | W20-5, W20-5a, W9-3 |
| Two lanes become one | Work Zone Merge and Lane Reduction Signs | W4-1, W4-2, W4-2D |
| Crew is working on the shoulder | Shoulder Closed Signs | W21-5, W21-5a |
| The road is closed to through traffic | Road Closed Signs | R11-2, R11-3, R11-4, W20-3 |
| Traffic must follow another route | Detour Signs | W20-2, M4-8, M4-9, M4-10 |
| The pavement itself is the hazard | Work Zone Road Surface Signs | W21-2, W8-7, W8-11, W8-15 |
| Drivers may have to stop or slow in the zone | Be Prepared to Stop and construction advisory speed plaques | CW3-4, W13-1P |
A typical lane closure on a two-lane road uses four signs in sequence: Road Work Ahead, One Lane Road Ahead, Flagger Symbol, then Be Prepared to Stop. Our sub-categories are arranged so you can build that sequence one sign at a time.
How to Choose the Right Size
MUTCD Table 6F-1 sets construction sign sizes by road type. Undersized signs are not allowed on faster roads. Oversized signs are always allowed.
- 36" x 36" is the standard size for conventional roads and the size most contractors order for street and county work.
- 48" x 48" is the standard for freeways and expressways, and the right choice on any road posted 55 mph or more.
- 30" x 30" is the minimum, allowed only on low-speed, low-volume roads such as residential streets and parking lots.
- Plaques follow the sign above them. A 36" diamond takes a 24" plaque, and a 48" diamond takes a 30" plaque.
If your crews work on both city streets and highways, order 48" signs. One size covers every job and the extra cost is small next to a failed inspection.
Which Reflective Sheeting Should You Order?
- High Intensity Prismatic (HIP) meets ASTM Type IV and the MUTCD minimum for ground-mounted work zone signs. It is the standard order for daytime work on conventional roads.
- Diamond Grade DG3 meets ASTM Type XI and returns about twice the light of HIP. Choose it for night work, high-speed corridors and signs mounted on the left side of the road.
- Diamond Grade Fluorescent Orange is DG3 with a fluorescent orange face. It is the brightest sign in daylight, dawn and dusk, and the grade most state DOTs now specify for work zones. It is also the best value for crews that reuse signs from project to project.
When a state or municipal contract calls out a sheeting grade, match the spec. When it does not, fluorescent orange is the safe default.
Where to Place Construction Signs
Advance warning signs go in a series before the work, spaced by road type under MUTCD Table 6C-1. On a low-speed urban street the spacing is about 100 feet between signs. On a rural highway it is 500 feet. On a freeway the first sign can sit half a mile ahead of the taper. The first sign a driver sees should always be Road Work Ahead.
Mount the bottom of a post-mounted sign at least 7 feet above the pavement in urban areas and 5 feet in rural areas. Portable sign stands may hold the sign as low as 1 foot above the pavement for short-term work. Cover or remove a sign when the condition it describes is not present, for example a flagger sign when no flagger is on duty. A sign that warns about nothing teaches drivers to ignore the next one.
Why Buy Construction Signs from RoadSigns.com
Our construction signs are made in the USA on .080" aluminum with prismatic sheeting applied to the exact MUTCD legend and border layout. Every size and sheeting combination is priced on the product page, so you can order one sign to replace a damaged one or a full lane-closure set without waiting on a quote. Quantity pricing applies automatically when you order the same sign in multiples. We are a registered federal supplier and ship nationwide from the factory. If your traffic control plan calls for a legend that is not in this category, email us and we will make it.
Construction Sign FAQ
Why are construction signs orange instead of yellow?
The MUTCD reserves orange for temporary traffic control so drivers can tell a work zone warning from a permanent road condition. A yellow curve sign stays for years. An orange curve sign means the curve is part of a detour or a shifted lane and will go away when the work is done.
Can I use a 30" x 30" sign to save money?
Only on low-speed, low-volume roads. On any conventional road the MUTCD standard is 36" x 36", and on freeways it is 48" x 48". An inspector can shut down a work zone over an undersized sign, so buy the size the road requires.
Do I need the distance printed on the sign or a separate plaque?
Either works. We stock Road Work Ahead, Lane Closed and Detour signs with 500 ft, 1000 ft, 1500 ft, 1/2 mile and 1 mile printed on the face, which is one less piece to mount. A blank version lets you add your own plaque when the distance changes from job to job.
When do I have to replace a construction sign?
Before any deployment where the sign is no longer in like-new condition. Look for fading, peeling or cracked sheeting, bent corners and dents that catch light at night. A sign that looks fine at noon can fail a retroreflectivity check after dark, so inspect at night at least once a season and keep spares on the truck.
Can I order a custom construction sign legend?
Yes. Send us the wording, size and sheeting grade from your traffic control plan and we will produce it on the same aluminum as our stock signs.