Optimal Driving Routes
Over the last few weeks, we discussed in class about the workings of traffic and how individual drivers affect the way traffic moves on certain routes. Traffic and optimal routes seem easy, but can be really complex due to people’s preferences and location. Two authors Marta Gonzalez and Antonio Lima describe a plethora of transportation research that delves deep into how drivers actually think and act on the road. According to the article, a lot of traffic predictor models are based on the assumption that drivers are rational and will take the optimal route that minimizes travel time. However, it is hard for route planners to effectively use user behavior because there is not a lot of empirical evidence that drivers will consistently choose the optimal route every time. It is definitely important to understand how humans subconsciously choose driving routes not only because of gaining a stronger grasp on human movement behavior but also can severely improve urban infrastructure. The article further describes the added benefit of beating and optimizing traffic and congestion because it costs Americans approximately $160 billion, 42 hours of extra travel time, and $960 worth of extra fuel.
One of the big questions to ask, though, is how people actually travel. The two authors note the fact that after studying and conducting research to look for travel patterns using a plethora of GPS data, people, for the most part, only use a select number of routes. Furthermore, people tend to have favorite routes and do not wander from their most used route. Similarly, the GPS data showed that half of people’s “favorite” routes are not considered optimal. Although it seems very obvious to take the most optimal route as dictated by a GPS or mapping service, people still choose to deviate from the most efficient path. Some studies show minor reasons such as choosing “routes going south rather than routes of equal lengths going north” or longer routes that are “straight at the beginning compared to shorter ones that are not”. In addition, in urban areas, it is much harder to take the best route because of buildings and more constant detours. It is really hard to pinpoint specific factors as to why people choose not to take a more optimal route.
The next study they conducted focused more on quantifying how far the people’s choices were from optimal. The researchers condescend and manipulated all of the routes sampled to start at the same point and end at the same point. They found that many of the routes are contained within an ellipse with the same shape. Furthermore, utilizing the ellipse demonstrates how direct a route is. The paper describes the term eccentricity which tells how elongated the ellipse is. The studies showed that it had an eccentricity of around 0.8 which means that the shape of the combined route is more of a circle rather than a straight line. Moreover, one interesting fact they concluded from the data was that in an urban setting, drivers are willing to take detours that are roughly proportional to the distance between their starting point and destination. In other words, routes that involved bigger detours usually are less traveled on, or are split into two separate trips.
Overall, it seems as though people are far from consistently taking the best route. The study also seems to reveal a solid amount of “quantifiable flexibility” in preferred driver’s routes. There are maybe solutions that can help reduce road congestion and induce more driver flexibility. For instance, there could be incentives for people that are willing to take longer routes. These studies can also significantly help planners to create and understand new routing techniques. And in the end, improve global and national infrastructure.
Link: http://theconversation.com/recalculating-by-not-driving-the-optimal-route-youre-causing-traffic-jams-56135