A municipal sanitation department in Xi'an, Shaanxi Province: Dongfeng D6 blue-plate 3-cubic-meter sludge tipper procurement case study. In Northwest China—especially in Xi'an and surrounding cities—municipal sanitation departments face a unique challenge: how to effectively control odor and leakage during sludge transportation while adapting to the high-wind-and-sand conditions of desertified climates. In early 2025, a district-level municipal sanitation unit in Xi'an (hereinafter referred to as 'the Unit') publicly tendered for a batch of compact sludge tippers to transport sludge following sewer network desilting operations within its jurisdiction. After multiple rounds of evaluation, five Dongfeng D6 blue-plate 3-cubic-meter sludge tippers manufactured by Chengli Special Purpose Vehicle Co., Ltd. (hereinafter 'Chengli') were delivered. This article analyzes the procurement decision logic from the perspective of the Unit’s fleet management director. I. Fleet Management Director’s Evaluation: From 'Headache' to 'Peace of Mind' "Our previous generation of tipper trucks caused constant headaches—especially during sandstorm seasons. The cargo box sealing strips would rapidly degrade, leading to sludge spillage onto roads. Not only did this affect urban aesthetics, but it also triggered frequent public complaints," stated Captain Li (a pseudonym), the Unit’s fleet director. Located on the Guanzhong Plain near the Loess Plateau, Xi'an experiences frequent springtime sandstorms, imposing exceptionally high requirements on vehicle dustproofing and sealing performance. After comparing offerings from multiple suppliers, Captain Li’s team focused their evaluation on Chengli’s Dongfeng D6 blue-plate 3-cubic-meter sludge tipper (model CLW5070GSSD6, built on a dedicated sludge-tipper chassis with full official certification). The chassis is based on the Dongfeng D6 series and equipped with a China VI-compliant engine; the superstructure is independently designed by Chengli. Captain Li noted: "Zhang Yue, Chengli’s sales manager (phone: ), arranged an on-site demonstration of the actual vehicle, highlighting the hydraulic locking mechanism and dual-layer sealing gasket on the rear cargo box lid. We conducted a live test using a high-pressure water jet for five minutes—the interior remained completely dry. That gave us great confidence." II. Dispatch Flexibility: Blue-Plate License Allows C-Class Driving License Operation—Unrestricted Urban Access The Unit’s daily operations cover both Xi'an’s historic urban core and newly developed districts, where narrow roads and strict traffic controls prevail. Prior to procurement, the team’s top concerns centered on vehicle dimensions and driver licensing restrictions. "Many heavy-duty sludge trucks require drivers holding Class B licenses—we face severe personnel shortages. By contrast, blue-plate vehicles can be operated with a Class C license, significantly lowering driver training costs," explained Captain Li. The Dongfeng D6 blue-plate 3-cubic-meter sludge tipper features a compact overall footprint (reference certified dimensions: approx. 5.5 m × 1.9 m × 2.2 m), small turning radius, and is ideally suited for operations in residential alleyways and adjacent to sewage manholes. Crucially, its rated payload capacity of 3 cubic meters (approx. 3–5 tons) complies fully with Xi'an’s blue-plate freight vehicle access regulations—eliminating the need for special permits and substantially improving dispatch efficiency. "Previously, we could only operate at night; now we can enter residential communities even during daytime hours—doubling our operational efficiency," said Captain Li. III. Fuel Consumption Monitoring Data: Economic Performance Exceeds Expectations During the first quarter after deployment, the Unit conducted dedicated fuel consumption monitoring. According to operational data provided by the fleet: • Average daily driving distance per vehicle: ~80–120 km (primarily short-h