Being particularly interested in human factors and perception-reaction delay after learning about transportation modeling, I surveyed the opportunity area for autonomous vehicles to optimize traffic at a simulated intersection.
Traffic in the Los Angeles metropolitan area ranks number 6 in the world for most time spent sitting idle, with residents spending over 100 hours a year in traffic. Autonomous vehicle technology, including various levels of automation and connectivity, has the potential to revolutionize traffic flows by increasing safety, and by optimizing time spent in traffic as well.
Autonomous vehicles pose value propositions that vary slightly depending on their level of automation, though overall falling categories including safety, parity, and optimization.
Safety: automation aims to reduce or eliminate human factors (to be discussed in further detail below), and these factors can pose safety issues in emergency situations. Humans experience a delay in decision making when faced with problems, and therefore, collisions occur
Optimization: going hand in hand with the previous statement about reducing perception reaction time is optimization of traffic flows.
Parity: Automation provides transport with the added mental perception of independence. to individuals that traditionally would not have the necessary facilities to do so. Technology becomes a friend, an assistant to bridge the gap between imparity and driving, to create ability.
Perception reaction delay is a key mechanism in transportation, and a particularly intriguing slice of the autonomous vehicles cake. It’s a great example of an opportunity area related directly to the intersection of human factors and technology.
When we are faced with situations that require instantaneous responses, our humanity is a detriment to our reaction time. Reactions are a decision; do you choose to dodge a foreign object thrown at you, do you choose to catch it? Or, alternatively, do you choose to destroy it mid-air so that it does not make detrimental contact with your person? The possibilities for actions to take and scenarios to unfold approach infinity. In regards to transportation engineering, perception reaction delay is the time that elapses between when a stimulus is presented and when a driver reacts to it. This might look like a shredded tire in the middle of the highway, a coffee cup thrown out the window of the car in front of you, or a car to your left swerving into your lane. Even a yellow light poses a choice; do you clear the intersection, or do you stop before the light? How fast do you stop? Do you accelerate in order to clear that light in time? The decision-making dilemma persists in any scenario.
Overall, the two general decisions a driver can make when greeted with these types of scenarios are to avoid/clear the car around the object, or to stop. In both scenarios, the car remains moving in the time between when the stimulus is presented and when the decision itself is made.
Perception reaction time can be modeled logically, and is mathematically represented as the following in stopping sight scenarios:
a → deceleration of the vehicle
v0 → approaching velocity of the vehicle
x → distance from stop line
δ → perception-reaction time