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

2026-05-26

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.