Selection of Weigh-in-Motion (WIM) Station Locations

1. Site Selection

📍 Prioritize locations on major freight routes with steady traffic flow and convenient law enforcement access:

💡 National/provincial trunk highways, major county roads, expressway entrances/exits, provincial and municipal boundaries Exits of large mining areas, ports, logistics parks, building material markets and other cargo sources.

💡 Approaches ahead of large bridges and long tunnels (for structural protection of bridges and tunnels). 📢 Locations to avoid: Urban downtown areas, sections with dense traffic signals, sharp curves and steep slopes.

🔴 General principle: Vehicles shall pass through at a constant speed on a straight and smooth road without braking, accelerating or lane changing.

2. Road Alignment (Critical for Measurement Accuracy)

(1)Horizontal Alignment The station shall be installed on a straight road section, with a straight stretch of no less than 200 meters ahead and behind the detection zone. ⚠️ Prohibited locations: Curves, ramps, overpass approaches and road diverging/merging sections.

(2) Pavement Smoothness

💡 Within 35 meters ahead and behind the detection zone, the pavement roughness shall be within ±3 mm. No potholes, cracks or loose surface shall be present.

📢 The density of asphalt or concrete pavement shall meet relevant standards. Pavement patches are not allowed, especially directly above sensors.

(3) Road Gradient

💡 Longitudinal and transverse gradients shall both be no greater than 2% and keep uniform.

🔴 The gradient shall remain consistent for no less than 35 meters ahead and behind the detection zone; a minimum of 25 meters is acceptable under budget constraints. Sections at the bottom/crest of slopes or grade change points are strictly prohibited.