Efficiency of routing and scheduling system for small and medium size enterprises utilizing vehicle location data

The routing and scheduling for trucks and vans in an urban road network depends critically on the state of the road network. Trucks and vans impose significant costs on other road users and the environment, so improved routing and scheduling benefits more than just the logistics industry. However, small and medium size enterprises (SMEs) in the logistics business cannot justify investment in planning systems. In this paper, an autonomous routing and scheduling system which is available to SMEs is proposed and the efficiency of the system is investigated. The proposed system accumulates vehicle location data in a central server and uses it to generate traffic information. Test simulations using a grid network demonstrate the effects of utilizing and sharing vehicle location data on delivery efficiency. The simulation results show that the improvement of delivery efficiency is mainly due to the reduction of penalty cost for early and late arrival at the customer location. It is also shown that the system leads to the buffer effect from variations in traffic conditions on delivery cost and this effect is enhanced by taking travel time uncertainty into consideration. It is further shown that the presence of measurement periods with insufficient data results in unreliable routing and scheduling. For a reliable system, data collection over a wider area is required rather than dense data in a subset of links.     

Experimental research on spray and combustion characteristics of the third generation conical spray

A new generation conical spray system for conventional diesel engines or premixed combustion diesel engines is introduced. By means of oriented impingement method, flexible spray penetration in design is realized. High-speed photograph was used to investigate the spatial distribution characteristics of the new spray for cases of different impingement angles and needle valve opening pressures. The results show that, by applying spray impingement orientation, fuel jets spread along the cone surface as shape of sectors, so the dispersion of jets is increased obviously. Changing on impingement angle leads to variation of penetration, which is critical in homogeneous mixture preparation. Due to the flexibility of spray penetration in design, the spray impingement on liner is avoided in a great extent. The results also indicate that higher needle valve opening pressure results in longer penetration and larger spray angle after impingement. Combustion characteristics of the impinged conical spray were studied in the 1135 type diesel engine. The new impinged conical spray system work smoothly in full load range with better fuel economy and lower emissions of NOx and soot than the original test engine.     

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自动货车车道（ATL）是一项缓解城际高速公路货车比例偏高问题的下一代物流技术. 本文提出了一种微观-中观混合交通仿真器,用于精确评估在大规模公路网上引入自动货车车道所引起的交通流变化,并设计集成框架以确保路径选择与微观-中观仿真器校核的一致性,使用扩展后的微观车辆跟驰模型和车道变换模型反映轿车与货车之间的相互作用. 通过3个仿真案例评价自动货车车道对交通流、货车比例、旅行时间及总旅行时间节省的影响. 最后,使用混合仿真器分析道路的安全性和交通事故对旅行时间的影响. 仿真结果表明：引入自动货车车道改变了New Tomei-Meishin高速公路及该路网中其它高速公路的交通量,缩短了旅行时间,提高了安全性. 应在大范围公路网络中分析自动货车车道系统,从而获得更精确的评价.     

Preliminary analysis on dynamic route choice behavior: Using probe‐vehicle data

Dynamic traffic assignment models have been attracting increasing attention with the progress of traffic management policies based on information technology. These dynamic estimation tools, however, just apply static route choice models either at only origin node or at every arrival node. This paper aims at providing some knowledge on drivers' dynamic route choice behavior using probe‐vehicle data. The results of analyses show that route choice behavior relates to the distance from driver's position to the destination and that dynamic route choice behavior is modeled better by considering decision process during the trip.