Mojtaba Moharrer, PhD
Mojtaba Moharrer, PhD

In a car-oriented society such as the United States, driving is more than a simple privilege.

The ability to drive can have a direct impact on one’s quality of life. This is especially true for older people and people with disabilities, for whom driving can equal independence.

At the same time, it is important to assure that these individuals are able to drive safely and see the road clearly.

While the overall importance of vision in conventional driving is clear, the exact relationship between vision and safe driving is not yet known. Studies have shown different and at times contradicting results.

Over the past ten years, I have been studying drivers’ behavior, traffic safety and cross-cultural differences in driving behavior. In my current position as a postdoctoral fellow in Dr. Gang Luo’s lab at the Schepens Eye Research Institute (SERI), my colleagues and I are investigating driving behavior among visually impaired drivers using a unique blend of video footage, GPS and GIS data, and information about vehicle acceleration and braking speeds.

Bioptic telescope

Figure 1. The bioptic telescope is used as a driving aid for visually impaired drivers.

Across the United States individuals with low visual acuity are among the regular cadre of drivers. These individuals use their vehicles to conduct the business of daily life. In many states individuals with visual acuity as low as 20/200 are legally allowed to drive with the help of a bioptic telescope (Figure 1).

The bioptic telescope: Seeing eye or blind spot?

Bioptic telescopes are installed on top of a person’s normal glasses and magnify the view of the road for the driver. The magnification compensates for reduced visual acuity and enables the driver to see details at distances comparable to normally-sighted drivers.

Despite the legality of driving with a bioptic telescope, the safety of these devices remains controversial. Critics argue that looking through a telescope causes a ring scotoma (blind area) that could obscure a crucial view of traffic at critical times (Figure 2), as well as changes in perspective and depth perception.

Despite the potential benefits and drawbacks, only a few studies have been conducted to assess the implications of bioptics for safe driving.

Driver's perspective using a bioptic telescope

Figure 2. A driver's perspective of the road using the bioptic telescope

My colleagues and I are investigating driving behavior and the use of the telescope during naturalistic driving.

We capture naturalistic driving behavior using video cameras to record several days or weeks of a research participant’s actual driving, without any intrusions or interventions. One of the main challenges for studying driving safety is the general rare nature of incidents/crashes. This makes using crashes as the sole measure for investigating safe driving difficult, and possibly questionable.

We use a digital recording device that mounts on top of the rear view mirror and is made of two cameras, one that records footage of the road and one that records the driver’s face. We also use a GPS device to track location, speed, acceleration and deceleration.

Crunching the data

To assess this vast collection of driving footage, our team created a data reduction system that automatically extracts the sections/times of driving that are considered “sections of interest,” using a combination of image processing, speed and the geographical location of the vehicle during the drive.

Sections of interest are classified as high-risk and include:

  • Curve driving (using GPS data)
  • Intersection negotiation (using GIS and GPS data)
  • Rapid change in speed (using speed data)
  • Turns (using GPS and image processing)
  • Changing lanes/passing (using image processing)

This process reduces the amount of data we need to review by 80-90 percent.

We then study the remaining data to assess the behavior of the drivers and find patterns in their use of bioptic telescopes. In addition to assessing overall driving behavior, we focus on scanning behavior, such as visually checking the road ahead and checking in mirrors prior to the start of a lane change.

Could self-driving cars be the answer?

While there has been a lot of buzz around automated driving, scientists believe that it will be a long time—possibly decades—before there are fully automated cars that can operate safely in any road or environmental condition.

However, the use of assistive technologies in cars have shown great potential for improving driving safety. Improvement of Advanced Driver-Assistance System (ADAS) and inclusion of technology in driving are pressing issues in the field of human factors and technology, especially research focused on drivers with different types/varying levels of disabilities.

The personal connection

In today’s world, being a successful researcher requires a diverse set of academic and non-academic skills. Working in Dr. Luo’s lab has allowed me to apply my expertise on a project that has immediate and sustainable practical implications. I have also had the opportunity to develop a wide range of personal and professional skills, including science communication.

Improving traffic safety is my passion (see my talk below), and every day I come to the lab hoping my research will help visually impaired drivers maintain their independence and keep themselves—and other drivers—safe on the road.

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