Project Title

Develop and Test Connected Vehicle Freeway Speed Harmonization Systems

Collaborating Universities

Virginia Tech
1424 S Main St.
Blacksburg, VA 24061

Principal Investigator(s)

Hesham Rakha (VT) - Email:
Ihab El-Shawarby (VT) - Email:

Funding Source(s) and Amounts Provided (by each agency or organization)

USDOT: $55,000 (Federal)
VDOT: $91,211 (Match)

Start Date


Completion Date



The goal of this research effort is to develop a dynamic speed harmonization application (SPD-HARM) that makes use of the frequently collected and rapidly disseminated multi-source data drawn from connected travelers, roadside sensors, and infrastructure, as depicted in Figure 1. The application may be a vehicle-integrated device (e.g., a vehicle manufacturer-installed or aftermarket integrated device), a personal wireless application (e.g., a smartphone or other handheld device), or another application capable of collecting, receiving, and disseminating movement and locational information. The goal of SPD-HARM would be to improve the nature, accuracy, precision, and speed of dynamic decision making by both system managers and system users.

In achieving the identified goal, the objective of the project is to develop speed decision algorithms to achieve the mobility, safety, and environmental goals of dynamic speed harmonization. A connected vehicle environment will enable systems and algorithms that can generate traffic condition predictions, alternative scenarios, and solution evaluations in real-time. This would entail developing a simulation-based optimization tool to compute the optimum speed recommendations. Note that this requires an increase in computational capability as well as long-term storage of historical data. Performance measurement will play an important role in evaluating and improving dynamic speed harmonization algorithms and methods.


1. Reduce crashes, whether due to speeding, poor visibility, inclement weather, or construction activities. Improved safety results, in terms of reduced crash rates and less severe crashes, have shown to be the most significant and consistent achievements across the deployments examined.
2. Although not the primary goal for most U.S. and international speed harmonization deployments, improvements in throughput, though modest, have sometimes been achieved.
3. Speed harmonization implementations have been shown to produce energy savings and environmental benefits.