Effect of LRT system on Travel Time

The Light Rail Transit (LRT) system can be considered as a viable alternative from a sustainable transportation perspective because of the lesser capital and operational costs compared to Rapid Rail Transit Systems (RRTS). The popularity of the LRT systems in the United States could be attributed to its capability in reducing congestion and delivering safer, more predictable commutes. The decision to implement LRT systems and to design its operational attributes are made after a comprehensive transportation planning process or a feasibility study. However, it is difficult to fully understand the effect of the LRT system on the region’s traffic from typical travel demand models. In that context, providing short-term evidence of LRT systems’ effect on traffic based on the varaince in travel time is illustrated in this page

Study area

The Blue Line LRT is the Charlotte region's first LRT service. It is 18.9 miles long and extends from I-485 at South Boulevard to UNC Charlotte’s main campus. A four-mile stretch of the new extension that connects Old Concord Road and UNC Charlotte main campus, through North Tryon St median, is shown in map.

Scenarios

Six different scenarios were considered in the analysis process- Before LRT Phase(Q1), Testing Phase(Q2), First month of LRT operation(Q3), Third Month of LRT operation(Q4), Sixth month of LRT operation(Q5), Ninth Month of LRT operation(Q6)

Analysis Procedure

The North Tryon study area is divided into small segments and coded with a single identification code, namely, Traffic Message Channel (TMC) ID. Six TMCs are considered in the analysis process. Red colored lines shown in the map indicates the TMCs. The blue dots in the map are the locations were the TMC level analysis results will pop up or appear.

TMC-level analysis

For each selected TMC, the travel time variation has been analyzed using Box-whisker diagrams. The 25th percentile travel time, 50th percentile travel time, 75th percentile travel time, Inter Quartile Range of travel times, distribution properties, and outliers were identified from the Box-Whisker diagram.

Conclusions

The effect of LRT on travel time reliability of the near vicinity corridors was analyzed for six different scenarios. Normalized travel times for TMCs are considered for the analysis process. Many links along the LRT corridor clearly showed improvement, while some of them showed increase in travel time during many operating scenarios, compared to the network without the LRT operation. To avoid delays at signalized intersections due to LRT operation, there exists a clear exhibit of alternate route choice. Overall, Link-level travel time reliability analysis is useful in finding locations or links where system control, regulation, advisory, and other strategies are needed to enhance route reliability.

D3 Boxplot Refernces