In recent years, with the continuous tightening of environmental protection policies—especially targeted rectification campaigns in the sewage treatment sector—municipal sanitation departments across the country have seen a significant increase in demand for special-purpose vehicles. Taking Yibin as an example, a district urban management bureau launched a procurement plan for sewage treatment vehicles in 2025, focusing specifically on CN6-compliant Dongfeng models with a 3308 mm wheelbase. Owing to their maneuverability and adaptability, such vehicles have become the top choice for small- and medium-scale sewage treatment projects. This article examines a government procurement case, compares blue-plate (C-license) and yellow-plate (B-license) vehicle options, and provides an in-depth analysis of Chengli Special Purpose Vehicle Co., Ltd.’s tailored solutions—supporting procurement entities in making efficient, informed decisions. I. Background of the Government Procurement Case In a tender project initiated by an environmental maintenance unit in a subdistrict of Yibin City, the objective was to procure a batch of sewage treatment vehicles for routine cleaning and transport operations targeting urban sewage wells and septic tanks. According to publicly released tender information, the budget was capped at approximately RMB 880,000, with two units planned for procurement. Tender requirements explicitly stipulated: CN6 emission compliance; chassis wheelbase of 3308 mm; integrated functionality covering suction, separation, and transport; and suitability for operation in narrow urban streets. Against this backdrop, multiple suppliers participated in the bidding process. Chengli Special Purpose Vehicle Co., Ltd. successfully delivered two CLW5070GSSD6 sewage treatment vehicles, leveraging its Dongfeng chassis advantages and mature upfitting solutions. Customer feedback highlighted outstanding performance in both operational efficiency and system stability. The core evaluation criteria in this case centered on balancing compliance with urban road height and width restrictions while ensuring robust sewage treatment capability. Chengli’s solution employed the Dongfeng 3308 mm wheelbase chassis, keeping overall vehicle length under 6 meters and height below 2.5 meters—perfectly aligned with municipal operational requirements. Following acceptance testing, the client reported that the vehicles maintained stable suction capacity even after eight consecutive hours of operation, achieving a sewage separation efficiency exceeding 95%. II. Comparative Analysis of Blue-Plate vs. Yellow-Plate Vehicles Selecting between blue-plate (drivable with C-class license) and yellow-plate (requiring B-class or higher license) vehicles is one of the most common challenges faced by procurement entities in sewage treatment vehicle selection. Below is a comparative analysis across four key dimensions: driver licensing requirements, operating costs, traffic access restrictions, and loading capacity. Comparison Dimension Blue-Plate Vehicle (C-License) Yellow-Plate Vehicle (B-License) Driver Licensing Requirement Operable with C1 or C2 license; lower driver recruitment cost Requires B-class or higher license; relatively scarce driver pool, with salary costs over 30% higher Annual Operating Cost Estimate Insurance: approx. RMB 12,000–18,000; lower toll and maintenance expenses; total annual operating cost approx. RMB 40,000–60,000 with optimized planning Insurance: approx. RMB 25,000–35,000; higher toll and maintenance expenses; total annual operating cost approx. RMB 70,000–100,000 Traffic Access Restrictions Permitted on most urban roads, elevated highways, and residential streets; unaffected by local traffic restriction policies Subject to restricted access in core urban zones of certain cities; requires special permits, potentially reducing dispatch efficiency Loading Capacity Tank volume: approx. 3–5 m³; ideal for small-scale, high-frequency operation