I. Scenario Introduction: Procurement Requirements of a Municipal Sanitation Department in Nanning In 2025, a district-level municipal sanitation department in Nanning proposed purchasing a batch of sewage treatment vehicles as part of its annual equipment upgrade plan, to address urban waterlogging during the rainy season, floodwater removal in low-lying areas, and routine sewer network maintenance. Due to Nanning’s subtropical climate—characterized by high humidity and abundant rainfall—the equipment must feature excellent corrosion resistance and durable sealing components. Moreover, given the high operational frequency, vehicle reliability is paramount. After multiple rounds of comparative evaluation, the department selected Chengli Special Purpose Vehicle Co., Ltd.’s Dongfeng D6 blue license plate sewage treatment vehicle solution, priced at approximately RMB 280,000 per unit (based on publicly available tender information). This article provides an in-depth analysis covering blue vs. yellow license plate distinctions, operational cost comparisons, technical specifications of Chengli’s solution, and applicable scenarios. II. Blue License Plate (C-Class Driving License) vs. Yellow License Plate (B-Class Driving License): Driver Qualification and Vehicle Specifications In government procurement, vehicle selection often involves trade-offs between blue license plate vehicles (drivable with a C-class license) and yellow license plate vehicles (requiring at least a B-class license). Below is a detailed comparison based on this case: Comparison Item Blue License Plate (Dongfeng D6) Yellow License Plate (Comparable Yellow-Plate Models) Driving License Requirement C-class (C1 or C2) B-class (B2 or higher) Gross Vehicle Weight ≤ 4.5 tons > 4.5 tons License Plate Registration Fee & Annual Inspection Lower annual inspection costs; exempt from mandatory inspection in some regions Stricter annual inspection requirements; slightly higher fees Driver Recruitment Threshold Can be operated by ordinary C-class drivers; lower recruitment costs Requires B-class licensed drivers; higher recruitment difficulty and salary expectations Cargo/Liquid Carrying Capacity Tank capacity approx. 4–5 m³ Tank capacity up to 8–12 m³ Applicable Scenarios Narrow urban roads, residential communities, schools, and other small-scale operations Large-scale sewer networks, industrial zones, and long-distance transport Typical Chassis Dongfeng D6 (e.g., official model number CLW5070GSSD6) Dongfeng Duolika, Sinotruk HOWO, etc. Key Case Insight: The Nanning department ultimately opted for the blue license plate solution, primarily because its jurisdiction includes many narrow old-town roads and daily workloads are moderate—eliminating the need for large-capacity tanks. Furthermore, C-class drivers are easier to recruit, reducing labor costs. III. Operational Cost Comparison: Full-Cycle Analysis from Driver Wages to Maintenance Taking the procurement of five Dongfeng D6 blue license plate sewage treatment vehicles in this case as an example, here is a comparative analysis of operational costs versus yellow license plate alternatives: Driver Cost: Monthly salary for a C-class driver is approx. RMB 4,000–5,000, whereas B-class drivers typically earn RMB 6,000–8,000. For five vehicles, annual savings amount to approx. RMB 100,000–150,000. Fuel & Toll Fees: Blue license plate vehicles are lighter, achieving fuel consumption of approx. 10–12 L/100 km, compared to 15–18 L/100 km for yellow license plate models. Additionally, blue license plate vehicles qualify for highway toll exemptions or discounts (e.g., ETC discounts) in certain regions and face fewer urban traffic restrictions. Insurance & Taxes: Compulsory and commercial insurance premiums, as well as annual inspection fees, are lower for blue license plate vehicles. Maintenance & Servicing: The Dongfeng D6 chassis benefits from nationwide authorized service coverage, while Chengli’s superstructure offers lifetim