Tuesday, June 20, 2017

OPINION - The Newest Stoplight To Avoid

Welcome to your newest form of torture, the stoplight at Dahlgren Road and Caledon Road (Routes 206 and 218 respectively). Before you yell at me and tell me that the light is a necessary evil, I will forewarn you that I only agree that some improvement was necessary there. However, I feel a traffic light is not one of them.

Traffic circles get a lot of negative press, and even more than normal here in King George. But before you shove those fingers in your ears and start yelling "LA! LA! LA!" let me remind you that the science is there to prove traffic circles work at not only moving traffic faster through the intersection but also doing it more safely than a typical stoplight.

Before we continue debating the pros and cons of lights and signs and circles, let's take a moment to look at a potential solution. VDOT has installed the stoplight and we all know they’re not likely to remove it anytime soon. Maybe we can find a solution that will make some of you happy. Or at least less upset at driving through yet another stoplight on your daily commute. With nearly 10,000 employees, Dahlgren is the host to our area’s primary employers. Factor in Potomac Elementary School during the school year, limited capacity on local roads, and it's a recipe for a commuter's nightmare.

What I propose is an alternative route to Dahlgren. My proposal is based on a few assumptions so let's get those out of the way first. I'm assuming that most of the traffic comes from the Fredericksburg area. I'm assuming that most of the traffic is going to Dahlgren's Main Gate. I'm assuming that we are all driving the speed limit because, well, we all know that’s the right thing to do.

To measure my distances, I used two points; Sealston Elementary School and the Dahlgren Post Office. I measured various routes using main roads and secondary roads, counted the stoplights, and even compare distances that are two lanes versus four lanes. Below is the end result of what I found.

Route Used
Total Distance
Number of Stoplights
2 Lanes vs. 4 Lanes
Route 3 to Route 206
19.6 miles
7 (Sealston, Hopyard, Post Office, KGMS, St. Paul's, WaWa, PES)
11.0 miles vs. 8.6 miles
Route 3 to 603 to Route 218 to Route 206
20.7 miles
4 (Sealston, St. Paul's, WaWa, PES)
20.7 miles vs. 0 miles
Route 3 to Route 205 to Highway 301 to Route 206
20.7 miles
10 (Sealston, Hopyard, Post Office, KGMS, KGHS, KGES, Rankins, Hillcrest, WaWa, PES)
4.2 miles* vs. 16.5 miles
Route 3 to Route 206 to 611 to Highway 301 to Route 206
21.8 miles
7 (Sealston, Hopyard, Post Office, KGMS, Hillcrest, WaWa, PES)
7.4 miles vs. 14.4 miles
Route 3 to Route 301 to Route 206
22.8 miles
11 (Sealston, Hopyard, Post Office, KGMS, KGHS, KGES, Tractor Supply, Rankins, Hillcrest, WaWa, PES)
2.9 miles* vs. 19.9 miles
Route 3 to 694 to Route 218 to Route 206
23.2 miles
4 (Sealston, St. Paul's, WaWa, PES)
18.4 miles vs. 4.8 miles

*The distance from St. Anthony’s Road to Tinsbloom Lane, where Route 3 goes to two lanes, is approximately 1.1 miles.

It’s pretty easy to see that the shortest distance is the tried and true Route 206 (#1). But when you look at #2 and #3, you’ll see the distance is only another mile further. For the fewest traffic lights, you’ll need to use #2 or #6. For the longest distance on four lane roads, #3 and #5 are your best bet while #2 has only two lane roads.

After crunching way more numbers and datasets than I expected, after learning more about the differences between geometric mean and harmonic mean, I finally stopped my circular calculations and decided to arrive at a ground-breaking opinion.

I say ground-breaking because I’m going to disagree with my own data as well as my own attempt at weighting the different routes based on these factors. In other words, I’m going to go with my gut. And my gut says, use option #3 (Route 3 to Route 205 to Highway 301 to Route 206). I feel like this gives you the best option to drop off your kids at all the different schools, it allows you to safely make left-hand turns, and it gives you the best combination of faster roads and shorter distances.

Distance (miles)
4 Lane %
Stoplight Time (seconds)

*To determine the best 2 vs. 4 Ratio, I subtracted the 4 lane distance in miles from the 2 lane distance in miles. This would give the routes with more 4 lane mileage a lower number, which would better align them with the other scores.
** The Stoplight Time is based on an average of 70 seconds per cycle. I then divided each cycle in half (35 seconds) and multiplied by the number of lights on the route.
***The Mean and the Average only differed by a small amount in the Distance and the Total columns. Because the difference was so small, I felt it wasn’t important enough to include this math in the chart.

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