Mile marker signs on interstates are both a convenience and a safety measure in that they provide travel progress information to motorists and essential location information for 911 emergency procedures. Motorists who report accidents need to be able to identify the location of a crash so that first responders will be able to deploy help from the appropriate facility as fast as possible. Providing crash location information becomes more difficult on complex urban highway interchanges. Inadequate ramp designation signing may lead to incorrect locations being called into the 911 dispatcher. This may cause delays in providing aid. The goal of the research performed in this study was to determine mile marker and ramp designation sign effectiveness using (1) a computer model of human nighttime legibility with a program called Tarvip, (2) a computer-based sign comprehension analysis, and (3) a road test validation. Tarvip provided the letter height and the legibility distance of the mile marker and ramp signs, while the comprehension analysis provided the design, content, and layout of the signs. The road test validated the results from Tarvip and the comprehension analysis.

Procurement Agency: MDSHA
Project Contact: Consultant: KMJ Consulting, Inc.

Capt. Henry De Vries or Michael L. Pack
Phone Number: Pack—301-403-4594
Email Address: PackML@umd.edu

The purpose of this research project was to (1) find the best design/deployment of mile markers and (2) find the best design for ramp designation signs so that motorists can pinpoint locations along the freeway and relay it to first responders, if needed.

View PDF file of Scope of Project.

Study and document best practices in mile markers and ramp designation signing, and develop and field test recommended signage.

This study conducted a comprehensive lab and field test of various sign types (fonts, sizes, materials, and layout). Based on the scores received during testing and the weightings determined by the steering committee the MUTCD D10-3 sign was found on average to have the best design, layout, and content for a Reference Location Sign. ). The MUTCD D10-3a sign had the best design, layout, and content for an Intermediate Reference Location Sign on average. The MUTCD D10-4 sign had the best design, layout, and content for an Enhanced Reference Location Sign on average. The sign that had the best design, layout, and content for an Intermediate Enhanced Reference Location Sign was the Indiana mile marker on average.

With regard to ramp signs, the New Jersey ramp sign was found on average to have the best design, layout, and content when it came to ramp signs. However, engineers should bear in mind that the New Jersey ramp sign conveys less information, as it does not contain a from-to mapping. Since there are fewer information elements, the legend was larger than in all other signs. Sign designers need to weigh the trade-off between content and legibility. For more complex interchanges, the New Jersey ramp sign might not be as effective. The final report explains this in more detail.

The Final Report was distributed to the full CIM PTC. Additionally, the CIM PTC may select to advance this Study on to AASHTO for national standards consideration.

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$50,000 project study (12-3E) and $80,796 evaluation (12a-3B)