Effects of rainfall on the weekday traffic flow in major cities of the Beijing-Tianjin-Hebei region, China, in 2021

Rainfall can bring uncertainties to the traffic flow and influence the normal function of urban transportation systems.The impact of precipitation on the urban traffic flow,especially the different impacts among cities and areas within a city,is worth investigating.Here,we analysed the impact of precipitation on the traffic flow in the urban areas of the Beijing-Tianjin-Hebei region by comparing the traffic flow in non-precipitation and rainy weather with different hourly precipitation intensities in 2021.The increase in the travel time index(TTI)is chosen to represent the influence of precipitation on the transportation system.The results show that the maximum of the average TTI increases on the city scale under various rainfall intensities by 3.3%,6.6%and 10.8%in Beijing,Tianjin and Shijiazhuang,respectively.In general,the increase in the TTI contributed by precipitation is the greatest at morning and afternoon peak hours,and the traffic congestion degree increases with the rainfall intensity.However,in the morning peak,afternoon peak and midday hours in Beijing and Tianjin,the influences of the weak rainfall intensity on the traffic flow are generally great,whereas the traffic congestion degree caused by heavy precipitation is relatively low.Particularly,in morning peak hours,the congestion reduction reaches approximately 2%,which may be related to the spatial difference in the impacts of precipitation on the traffic flow and the changes in people's travel intention under different rainfall intensities.The findings can help better understand the relationship between rainfall and urban traffic flow characteristics and also potentially contribute to the development of impact-oriented climate predictions.

Implementation of a drainage information, analysis and management system

An integrated drainage information, analysis and management system （DIAMS） was developed and implemented for the New Jersey Department of Transportation （N/DOT）. The purpose of the DIAMS is to provide a useful tool for managers to evaluate drainage infrastructure, to facilitate the determination of the present costs of preserving those in- frastructures, and to make decisions regarding the optimal use of their infrastructure budgets. The impetus for DIAMS is the culvert information management system （CIMS）, which is developed to manage the data for culvert pipes. DIAMS maintains and summa- rizes accumulated inspection data for all types of drainage infrastructure assets, including pipes, inlet/outlet structures, outfalls and manufactured treatment devices. DIAMS capa- bilities include identifying drainage infrastructure, maintaining inspection history, map- ping locations, predicting service life based on the current condition states, and assessing present asset value. It also includes unit cost values of 72 standard items to estimate the current cost for new assets with the ability to adjust for future inflation. In addition, DIAMS contains several different repair, rehabilitation and replacement options to remedy the drainage infrastructure. DIAMS can analyze asset information and determine decisions to inspect, rehabilitate, replace or do nothing at the project and network levels by comparing costs with risks and failures. Costs may be optimized to meet annual maintenance budget allocations by pfioritizing drainage infrastructure needing inspection, cleaning and repair. DIAMS functional modules include vendor data uploading, asset identification, system administration and financial analysis. Among the significant performance feature of DIAMS is its proactive nature, which affords decision makers the means of conducting a comprehensive financial analysis to determine the optimal proactive schedule for the proper maintenance actions and to prioritize them accordingly. Benefits of DIAMS include long-term savings that accrue by adopting optimized preventive maintenance strategies and facilitating compliance with Governmental Accounting Standards Board （GASB） and federal storm water regulations.