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It was also noted that activities such as street repair or resur- SUGGESTIONS
facing require the IPM system to be removed and reinstalled
or lost. This is not unique to IPM system applications, but Based on the information gathered through this synthesis
challenges the longevity of any type of roadway instrumen- effort, illuminated, active, IPM systems show potential for
tation. Again, barrier- or post-mounted IPM systems are enhancing: (1) warning through school and construction
less likely to be affected by roadway repair or resurfacing zones, at highwayrail crossings, at horizontal curves, and
activities. during adverse weather; (2) guidance through multiple-turn
lanes, at merge locations, and through tunnels; (3) regulation
at intersection stop bars and where left turns are prohibited;
Costs and (4) illumination at vehicle and truck inspection points
and environmentally sensitive areas. Direct benefits of IPM
Costs for IPM system applications range significantly, from systems in each of these applications cannot be quantified
$5,000 to $100,000. Factors affecting cost include the length conclusively because few acceptable evaluations of recent
and layout of the application and the subsequent number of IPM system applications have been performed, and a lack of
markers required; specific features of the IPM system (e.g., installation, operation, and maintenance guidance is likely
unidirectional or bidirectional displays and operational modes); confounding system performance. As such, suggestions to
the availability and nature (e.g., solar) of power at the site; focus future research and accelerate successful applications
the condition of the pavement and any remedial actions of IPM systems fall into two categories: (1) research and eval-
required before IPM system installation; and traffic control uation and (2) standards and guidelines.
requirements. In general, implementing agencies do not con-
sider IPM systems to be a "low-cost" alternative to traditional
traffic control devices and suggest that their use be limited to Research and Evaluation
critical locations. Opportunities for federal funding to support
IPM system implementation may be constrained by propri- · Development of a robust and standardized methodol-
etary issues (i.e., FHWA typically requires system bids from ogy for evaluating IPM systems would help to ensure
three or more vendors; patented products may not be approved that some level of consistency is achieved in the evalu-
for widespread implementation). ation of these treatments. The functional breadth of more
recent IPM system applications (i.e., to warn, guide,
regulate, or provide illumination) requires an adaptable
Perceived and Measured Effectiveness methodology that encompasses a wide range of perfor-
mance measures.
Few formal evaluations have been performed to determine · Agencies that currently operate IPM systems are
the effectiveness of IPM systems in enhancing roadway safety, encouraged to evaluate their effectiveness and docu-
operations, or aesthetics. Pedestrian crosswalk applications ment subsequent findings so that others can benefit
have been most frequently studied; IPM systems have gen- from their experiences. In lieu of a standardized eval-
erally been shown to increase vehicle driver awareness, uation methodology, agencies could focus on obtain-
increase vehicle yielding, reduce vehicle approach speeds, ing a sufficiently large data sample over a reasonable
reduce vehicle/pedestrian conflicts, and reduce pedestrian wait observation period to enhance the credibility of their
times. findings.
· Additional research, with the following focus, could
Considering broader applications of IPM systems, addi- support subsequent development of IPM system guide-
tional studies have generally shown a reduction in vehicle lines and standards:
speeds, improved lane-tracking, increased road user aware- Equipment specifications addressing the illumina-
ness, and high public acceptance. More recent studies have tion source, housing and lens, power source, system
been conducted in response to FHWA's requirements for controller and enclosure;
experimental status. Early results reported from these studies Operational specifications addressing system acti-
show promise but are generally based on limited data and, as vation, marker color, marker flash rates, and chase
such, cannot be considered conclusive. sequences;
Installation methods including system layout and
Implementing agencies provided significant anecdotal spacing;
information through this synthesis effort purporting the effec- Maintenance requirements;
tiveness of IPM systems in enhancing various aspects of road- Human factors (e.g., effects of glare and comprehen-
way safety, operations, or aesthetics depending on the nature sion); and
of the application. A high overall degree of IPM system Safety (e.g., overdriving and collision with nonillu-
satisfaction was reported despite any installation or mainte- minated objects).
nance challenges encountered. Further, implementing agencies · Development of an Internet-based clearinghouse could
noted a high level of public support for and acceptance of support exchange of practical information (e.g., instal-
IPM systems. lation lessons learned, annual maintenance costs, and
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warranty recommendations) regarding IPM system use · Warrants are likely not required or appropriate for IPM
among public agencies. systems; IPM systems typically supplement existing traf-
fic control treatments and/or devices.
· Methods to describe the relationship between IPM sys-
Standards and Guidelines tems and other ITS devices and systems and promote their
use within ITS architectures and planning efforts could be
· An expanded breadth and depth of coverage of IPM beneficial in encouraging implementation. These meth-
systems within the MUTCD is encouraged. The breadth ods could consider how IPM systems would interface
of IPM system application and subsequent function with communications protocols and other equipment, and
suggests a similar required breadth in related standards how they could provide feedback to transportation system
and guidelines. operators to report operational status.
