Government procurement case of Dongfeng D6 blue license plate sewage treatment vehicle in Lhasa: An efficient low-temperature solution. In Lhasa, located at an altitude exceeding 3,600 meters, winter temperatures frequently drop below -15°C, posing severe challenges for municipal sanitation departments’ sewage treatment vehicles—hydraulic system freezing, difficult engine starts, and pipeline ice blockages. These ‘plateau-related ailments’ once caused significant headaches for Mr. Wang, fleet management director of a municipal sanitation department. By the end of 2025, they procured 10 units of Chengli Special Purpose Automobile’s Dongfeng D6 blue license plate sewage treatment vehicle (model CLW5070GSSD6). After one full winter of operation, Mr. Wang offered a fair assessment: “These vehicles have improved our winter operational efficiency by at least 30%.” I. Fleet Management Director’s Evaluation: From “Headache” to “Peace of Mind” “Previously, we used modified water-sprinkling trucks for sewage treatment; by November, they were practically immobilized,” recalled Mr. Wang. “Hydraulic oil thickened like paste, requiring a 30-minute preheating period before startup—and we even had to use blowtorches to warm pipelines.” In 2025, this municipal sanitation department selected Chengli Special Purpose Automobile’s Dongfeng D6 blue license plate solution through open tendering. According to publicly available tender information, the project budget was capped at approximately RMB 282,000 per unit, with an average unit price around RMB 240,000, delivering a total of 10 units. Mr. Wang particularly emphasized the professionalism of Chengli’s after-sales team: “Mr. Zhang Yue (), Chengli’s account manager, led a team on-site to Lhasa and implemented three critical adaptations for plateau conditions: replacing all hydraulic oil with low-temperature-resistant grade, installing an engine preheating system, and insulating all pipelines. Though seemingly simple, these modifications delivered immediate and tangible results.” “From November 2025 to March 2026, under ambient temperatures as low as -15°C, these vehicles started instantly upon ignition, with highly responsive and smooth hydraulic systems—no lag or sluggishness whatsoever. Chengli’s promise—‘chassis covered under nationwide warranty; superstructure supported with lifetime service’—was truly validated this time.” — Fleet Management Director, Municipal Sanitation Department II. Dispatch Flexibility: Blue License Plate Advantages Enhanced by Plateau Adaptation The Dongfeng D6 chassis inherently offers advantages including C-class driver’s license operability and no urban driving restrictions—advantages further amplified in Lhasa. This municipal sanitation department serves both narrow alleyways in the historic old town and complex terrain in suburban-urban fringe areas. “The compact turning radius and overall length under 6 meters enable seamless access into narrow lanes for operations,” explained Mr. Wang. Chengli equipped this model with the Dongfeng D6 chassis (wheelbase: 3,308 mm); the official vehicle model is CLW5070GSSD6, with a rated payload capacity of approximately 3.5 tons and a tank volume of about 5 cubic meters. Compared to conventional 8-cubic-meter yellow license plate vehicles, these blue license plate units achieve higher traffic efficiency within Lhasa’s old town and eliminate the need for drivers holding Class B2 licenses—reducing recruitment complexity. “For dispatch, we divided the 10 units into two groups: five assigned to routine daily sewage treatment in the old town, and five retained as mobile response units for emergency overflow incidents. Thanks to their compact size and maneuverability, five units now cover the same operational scope previously handled by three 8-cubic-meter vehicles,” added Mr. Wang. III. Fuel Consumption Monitoring Data: Economic Efficiency Under Plateau Conditions