Choosing the wrong Truck-Mounted Attenuator (TMA) doesn’t just waste money—it risks lives and triggers $50,000–$250,000 OSHA/Caltrans fines. Western Highways Traffic Safety has supplied and maintained MASH-certified TMAs for California contractors since 2008. In the last 24 months alone, we’ve equipped 680+ vehicles with zero liability incidents and 100% Caltrans inspection pass rate.
This guide gives you the exact decision matrix we use with Caltrans, Cal Cities, and every major highway contractor to select the correct TMA—every time.
1. Start with Posted Speed & Facility Type (MASH Test Level Required)
| Posted Speed Limit | Facility Type | Required MASH Test Level | Minimum TMA Weight Class |
|---|---|---|---|
| ≤ 35 mph | Local streets, residential | TL-2 | 100-series (2,100 lbs) |
| 40–50 mph | Arterials, collectors | TL-2 or TL-3 | 100 or 225-series |
| ≥ 55 mph | Freeways, expressways, rural highways | TL-3 | 225-series (4,500+ lbs) |
Rule: Never use a TL-2 TMA on a 60+ mph facility. Caltrans will red-tag the truck instantly.
2. Match Host Vehicle GVWR to TMA Compatibility Chart
| Host Truck GVWR | Compatible TMA Models (2025) | Max Impact Rating |
|---|---|---|
| 10,000–15,000 lbs | TrafFix Scorpion II 100, Verdeg Vervex VPS-100 | 62 mph (100 km/h) |
| 15,001–26,000 lbs | Scorpion II 225, Verdek VPS-225, Trinity MPS-350 | 70 mph (113 km/h) |
| > 26,000 lbs (Class 7–8 | Trinity Highway TL-3 70K, Verdek VPS-350 Heavy Hauler | 70 mph |
Fact: Using an under-weight TMA on an over-weight truck voids MASH certification and your liability insurance.
3. Choose Cartridge Style: Scissor-Lift vs. Fixed-Tilt vs. 90° Vertical
| Style | Best Application | Deployment Time | Storage Height | Cost Range |
|---|---|---|---|---|
| Scissor-Lift | Moving lane closures, daily use | 60–90 sec | 13–14 ft | |
| Fixed-Tilt (60°) | Long-term stationary (paving, striping) | 30–45 sec | 15–17 ft | $$ |
| 90° Vertical Stow | Low-clearance bridges, urban work, transport | 15 sec | 8–9 ft | $$$ |
Most popular in California: Scorpion II C-Series with 90° vertical stow—fits under 10-ft overpasses and deploys fastest.
4. Arrow Board & Lighting Requirements by State
| State | Minimum Arrow Board Size | Required Lighting |
|---|---|---|
| California | 60″×30″ Type C | 4-corner strobes + sequential chevrons |
| Arizona | 48″×24″ Type C | Amber strobes only |
| Nevada | 60″×30″ Type C | Full sequential + work lights |
| Texas | 60″×30″ Type D | TMA must have integrated truck lighting sync |
Western Highways pre-wires every TMA with California-compliant Wanco or SolarTech boards—plug-and-play.
5. Critical Add-Ons That Prevent Fines & Accidents
| Add-On | Why It’s Non-Negotiable in 2025 | Cost |
|---|---|---|
| Impact-activated camera | Proves TMA was down during rear-end collision | $850 |
| GPS + telematics | Required by many prime contractors for billing | $45/mo |
| Backup alarm & strobe sync | Cal/OSHA hearing & visibility rules | $420 |
| Extended warranty cartridge | Covers crash replacement up to 3 events | $1,200/yr |
6. Real-World TMA Selection Examples (2024–2025 Jobs)
| Project Type | Speed | Truck GVWR | TMA Chosen | Reason |
|---|---|---|---|---|
| I-5 repaving (night work) | 70 mph | 26,500 lbs | Scorpion II 225 Vertical-Stow | Low clearance + fast deploy |
| City of Fresno arterial resurfacing | 45 mph | 14,500 lbs | TrafFix Scorpion II 100 Tilt | Budget + local roads only |
| CA-99 widening (rural) | 70 mph | 33,000 lbs | Verdek VPS-350 Heavy Hauler | Maximum protection for 80-ft spacing |
All units passed Caltrans safety meetings with zero comments.
7. Quick Reference Decision Tree (Print & Keep in Truck)
- What is the posted speed? → Determines TL-2 vs TL-3
- What is the truck GVWR? → Determines 100 vs 225 vs 350 series
- Daily or stationary work? → Scissor vs tilt vs vertical
- Clearance restrictions? → Vertical stow required
- State-specific lighting? → Pre-wire accordingly
Why Contractors Trust Western Highways for TMA Selection
- Only authorized California dealer for TrafFix Scorpion II, Verdek, and Trinity
- In-house MASH crash-test library and spec sheets for every model
- Same-day/next-day delivery from Porterville, CA stock
- Full installation, wiring, and Caltrans decal service
- Rental fleet available if you’re testing before buying
Get it wrong once and you’ll pay for it forever. Get it right the first time with Western Highways.
Call +1 (559) 785-1400 or email info@westernhighwaystrafficsafety.com for your free TMA selector worksheet and current inventory list.
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Your crew’s safety—and your bottom line—depend on the right TMA. Let the experts make sure you have it.
