Traffic on Washington area highways ahead of the upcoming Memorial Day holiday weekend is expected to reach its worst point on Thursday afternoon, running counter to a common perception that the Friday before the holiday weekend is the worst time to travel.
In a recent analysis, researchers at the Transportation Planning Board examined historical travel speed information on the region's freeways and several major arterial highways in the days leading up to the holiday weekend. The analysis used commercially available speed information from the last five years provided anonymously by drivers and other travelers via their GPS-equipped smartphones and navigation devices.
The analysis found that the average travel speed during the pre-holiday week dropped to its lowest point between 5:00 and 6:00 p.m. on Thursday afternoon. Traffic on Thursday was consistently worse than traffic on Friday, surpassing it in each of the five years that were studied.
More: See the full Memorial Day traffic analysis
Although the TPB study found that Thursday saw the slowest average hourly travel speed of the three days leading up to the holiday, it also found that Friday sees traffic-related slowdowns over a longer period of the day, beginning as early as 11:00 a.m. and lasting into the evening. The prolonged slowdown is commonly observed during non-holiday weeks as well but the magnitude of the slowdown on the Friday before Memorial Day is greater thanks to the additional holiday-related travel.
The TPB researchers who carried out the recent analysis attribute the Thursday afternoon peak to two overlapping travel trends. One is that Thursday afternoons already routinely see the worst traffic conditions during a typical non-holiday week -- thanks to regular rush-hour commuter traffic. The other trend is that some holiday travelers look to get an early start to the weekend by leaving town on Thursday. Together, the two trends add up to make the worst traffic day of the pre-holiday week. Some years, like 2014, the Thursday before Memorial Day is among the worst traffic days of the entire year.
The mildly counterintuitive finding of the TPB's most recent analysis mirrors a trend that TPB researchers identified last November related to Thanksgiving-week travel.
The November analysis found that the Tuesday before Thanksgiving saw the worst traffic conditions on major area roadways, even though many people think that the Wednesday before Thanksgiving has the most significant slowdowns and is the day to avoid. The TPB's researchers theorize that the peak on the Tuesday before Thanksgiving is also the result of an overlap between regular weekday traffic and early getaway travelers.
More: Researchers Identify Busiest Times, Roadways for Thanksgiving-Week Drivers
The findings of the TPB's recent holiday-week traffic analyses are of use to both travelers and transportation agencies seeking to avoid or manage the worst impacts of holiday-related travel. Similar analysis can also help travelers and agencies better understand back-ups resulting from special events and severe weather.
Past TPB analyses using the speed data from GPS-equipped smartphones and navigation devices have examined the traffic impacts of an observed decline in driving following the national economic recession, the before-and-after effects of the new Intercounty Connector in Maryland, and changes in driving patterns during summer months when schools are out and Congress is in recess.
Each quarter, the TPB publishes a report summarizing the latest hour-by-hour trends in congestion on area roadways and highlighting the effects of any special traffic events that occurred during the study period. The quarterly reports, each of which has a unique story to tell about regional travel patterns, are available at www.mwcog.org/congestion. The page also features a regularly updated "Congestion Dashboard."