Intersection Control Evaluation (ICE)

Beginning in 2020, the UDOT Traffic & Safety Division implemented an intersection control evaluation (ICE) process, with the intent of reducing severe crashes, making more informed infrastructure decisions, and improving mobility. The ICE process is a data-driven, performance-based approach used to objectively screen intersection alternatives and identify optimal geometric and control solutions.

An ICE study formally evaluates safety and delay reduction benefits of alternatives as well as initial capital, operations, and maintenance costs over the life cycle of the intersection. Using these results, a life-cycle benefit-cost ratio is calculated for each alternative. This allows UDOT to determine the best intersection configuration for preventing crashes and reducing delay at the lowest overall cost.

Screening Process

The ICE process is initiated through each UDOT Region's Traffic Operations Engineer. Additionally, all traffic studies that are completed through the formal UDOT traffic studies process are reviewed to determine if they are potential ICE study candidates. Potential candidates generally include:

• Intersections that have a history of severe crashes or an identified crash pattern.

• Intersections that are found to warrant a change in intersection control, such as a new traffic signal.

• Intersections that meet warrants for a major change, such as dual left-turn lanes. 

Locations that are identified as ICE study candidates undergo a preliminary analysis using two tools developed by the Federal Highway Administration (FHWA); the Capacity Analysis for Planning of Junctions (CAP-X) and Safety Performance for Intersection Control Evaluation (SPICE) tools. These preliminary analysis tools assess potential intersection configurations based on the estimated capacity and their ability to reduce crashes. Preliminary findings are generally discussed at a field review with UDOT Region staff and key stakeholders. An ICE determination meeting is then held to determine if an intersection, and any related alternative configurations discussed during the field review, should be recommended for a full ICE study.

ICE Study

A full ICE study typically takes about 60 days to complete. The study includes a preliminary design and detailed operational, safety, and capital costs analysis of the intersection and any alternative configurations.

An operational analysis identifies the potential reduction in delay, which is quantified using a benefit-cost calculation. Operational analyses are also completed for a future 20-year horizon to account for future traffic growth and planned changes and to ensure that the intersection will operate well in the future.

Safety is evaluated using a predictive safety model based on Highway Safety Manual (HSM) methodologies that predict whether crashes will increase or decrease for a particular intersection configuration. These are also quantified in a benefit-cost calculation.

Initial capital costs, as well as the life-cycle operation and maintenance costs for each intersection configuration are also calculated. Finally, using all of these metrics, an overall life-cycle benefit-cost ratio is calculated for each configuration to identify which is the most cost-effective, safe, and efficient. Each ICE study includes planning level concept layouts, level-of-service analyses for both existing and future 2040 scenarios, and a life-cycle benefit-cost evaluation discussed above.

Alternative configurations that show a significant safety benefit may qualify for Highway Safety Improvement Program (HSIP) funds to assist with intersection design and construction efforts.