The Interchange Safety Analysis Tool Enhanced (ISATe) provides design and safety engineers with an automated tool for assessing the safety effects of basic geometric design of freeways and interchanges. The predictive methods employed in ISATe are similar to the crash prediction methods in the Highway Safety Manual (HSM).
ISATe has applications for several types of analysis, including:

• Application 1—Estimating the Safety Performance of an Existing Interchange.
• Application 2—Predicting the Safety Performance of Design Alternatives for a New Interchange.
• Application 3—Predicting the Safety Performance of Design Alternatives for an Existing Interchange.

ISATe can be used to evaluate the following basic freeway and interchange components:

• Freeway sections (with or without speed-change lanes).
• Ramps or collector-distributor roads.
• Crossroad ramp terminals.

Note that the tool cannot be used to evaluate crossroad segments at an interchange, but Chapters 10 through 12 of the HSM can be used for this purpose.
ISATe can also be used to evaluate combinations of components, including:

• A freeway section comprised of several consecutive freeway segments.
• A freeway section within an interchange area with one or more freeway speed-change lanes.
• An interchange ramp comprised of one or more segments.
• An interchange consisting of one or more ramps and related ramp terminals.