【正文】 電子地圖中選擇最佳行車路線來優(yōu)化運輸網(wǎng)絡(luò)的交通狀況。 圖 3 十字路口單位 (A)，路邊單位 (B)和車輛單位 (C)，以及他們所在公路網(wǎng)絡(luò)的十字路口 十字路口單位的主要功能是接收并分析來自其他單位的信息來控制交通燈。從一位個別的司機或乘客來看，該目標(biāo)是以最小的代價安全地到達(dá)目的地。13]，如果一個車輛單位接收來自超過三個結(jié)點的信息，就能計算出它的位置 (x,y)和速度 v。 在這些參數(shù)中， 1)一些是固定的 ,例如馬路數(shù)和連接長度 。在程序常駐及運行的地方， MCU整合了處理機和存儲器。 控制子系統(tǒng)控制十字路口交通訊號燈。與隨機選擇算法相比 , 我們的算法摹擬出來的結(jié)果顯示交通網(wǎng)絡(luò)的公路平均速度和效率有了明顯地改善。 in [6], Di Febbraro presents a hybrid Petri Net module to address the problem of intersection signal lights coordination. The control subsystem controls the signal lights on the intersection. The guiding subsystem provides the realtime traffic information for the drivers to select the best route. The navigation subsystem uses satellite signal such as GPS to locate the specific vehicle, and with the help of electronic map, select the optimal route for the vehicle. One shortage of the systems mentioned above is that the sensors can only detect the vehicles in a fixed spot. They can not track the vehicles out of the spot. Clearly, if we can monitor and measure the traffic status dynamically in real time, an efficient traffic control will be easier to realize. With the development of microelectronic and puter technologies, the lowpowerconsumption, lowcost and relatively powerful wireless sensor work (WSN) technology has been applied in many areas[79]. However, the application of WSN in the traffic control system is rarely documented. In [10], we proposed a WSNbased system for an efficient traffic control in an isolated road intersection. This paper extends our previous work to a transportation work. A WSNbased traffic control, guiding, and navigation system is proposed to optimize the traffic in a transportation work. The rest of this paper is organized as follows: Section 2 describes the structure of the proposed WSNbased traffic control system. Section 3 describes the optimization algorithm for the traffic work. The simulation results and some discussions are presented in Section 4. Finally, Section 5 concludes this paper. 2. System Structure . WSN Module WSN module is a basic ponent in our traffic control system. As illustrated in Fig. 1, a WSN module prises of 3 main ponents, ., RF (Radio Frequency), MCU (Micro Control Unit) and Power Supply. The RF encodes, modulates and sends the signal. Also it receives, decodes and demodulates the signal as well. MCU integrates processor and memories, where the programs resides and executes. The Power Supply supplies the power to entire module. In the proposed system, WSN modules are widely distributed on vehicles, roadsides and intersections to collect, transfer and analyze the traffic information. See section for details. . Urban Traffic Network Several different facilities are installed in the urban traffic work to perform their specific functions. For example, the Signal Lights are installed in the road intersection to directly control the vehicle through the intersection。 and the intersection unit on the intersection. The main function of intersection unit is to receive and analyze the information from other units to control the signal light. The main function of roadside unit is to gather the information of the vehicles around, and transfer it to the intersection unit. (Roadside units are installed on the lamp posts along both sides of the road every 50~200m according to the wireless cover range.) The main function of the vehicle unit is to measure the vehicle parameters and transfer them to the roadside units. (Vehicle unit is installed in every vehicle.) The intersection unit, roadside units and vehicle units are denoted as A, B and C in Fig. 2. Roadside units broadcast messages every second. A m