Holiday Travel Trends
STL will continue to improve the Virginia Holiday Travel Trends website. The Holiday Travel Trends project uses travel time data from INRIX, and incident data from VDOT. During the course of the 2013 – 2014 fiscal year STL will:
- Enhance current procedure for establishing congestion levels, to take into account the geographical characteristics of the road (mountainous terrain or flat terrain) and reference speeds in addition to speed limits and population density characteristics (rural, urban). Other possible factors that might affect congestion levels will be studied and, if necessary, taken into account.
- Enhance current data cleaning procedures, particularly with respect to incorporating incidents.
- Including weather data, either from VaTraffic or from NCDC (National Climatic Data Center).
- Create the Holiday Travel Trends application for the 2013 Thanksgiving Holiday Period, and 2014 Memorial Day Weekend.
- Investigate the feasibility of porting the application to holidays with fixed days of the month (like Christmas, New Year, and Independence Day). (The current application and data processing has been developed for holidays falling on fixed days of the week: Thanksgiving Holiday Period Wed – Sun, Memorial Day Holiday Period Fri – Mon, and Labor Day Holiday Period Fri – Mon.)
Photos and Media
The project aims to present the historic congestion trends on the Virginia interstate system during major holiday periods. It has two parts: (1) computation of congestion trends and (2) visualization. The congestion trends are visualized on an online as one of three levels, color-coded using the usual GREEN-YELLOW-RED color scheme using Google Maps.
The spatial extent of the project is the Virginia interstate system. Until now historic congestion trends have been generated for these major holidays: Thanksgiving 2011, Thanksgiving 2012, Memorial Day 2013, Thanksgiving 2013, and Memorial Day 2014. VDOT is currently working on congestion trends for Labor Day 2014.
Congestion trends were calculated using private-provider vehicle probe-based speed data. VDOT is purchasing speed data from INRIX for the entire state and this data has been used for all the holiday periods. The entire interstate system is covered.
The congestion trends are not predictive in nature; they are historical averages of traffic conditions for the same holiday travel period from previous years. To account for changes in traffic due to non-recurring events (incidents, weather, work zones, etc.), and missing or inaccurate data readings, data from more than one year is necessary. A rolling window of three years was considered optimal to compute the historical congestion trends, traffic older than that could have been very different from current traffic and so irrelevant or even deleterious when trying to estimate current congestion trends.
The historic holiday congestion trends computation has the following steps:
- Standard Deviation Threshold Selection
- Data Aggregation
- Speed Data Processing
- Incident Mapping
- Outlier Elimination
- Data Smoothing
- RHOV Processing
- Corrections Based on Local Characteristics
Previous Virginia Holiday Travel Trends websites:
2014 Virginia Memorial Day Weekend Holiday Travel Trends
2013 Virginia Thanksgiving Holiday Travel Trends
2013 Virginia Memorial Day Weekend Holiday Travel Trends
2012 Virginia Thanksgiving Holiday Travel Trends