Civil Engineering Reference
In-Depth Information
15.7.3 Road User Benets
Examples of system operating bene
ts for various types of
incident management
strategies are detailed in [
4
]. Reported bene
ts include the following:
Effective traf
c incident management reduces incident duration by 30
-
50 %
Road weather information systems reduce crash rates from 7 to 80 %
Dynamic message signs reduce crashes by 3 % and improved on-time perfor-
mance up to 15 %
Work zone management reduces system delays up to 50 %
Active traf
c management increases traf
c throughput up to 7 %, and decreases
incidents up to 50 %
15.8 Summary Assessment of Experiences
in Managing/Mitigating Nonrecurring Congestion
A 2008 report by Cambridge Systematics et al. [
7
] contains a review and synthesis
of congestion management practices in US metropolitan areas. The report covered
both non-recurring and recurring congestion.
The mitigating impacts of strategies that were applied to
nonrecurring conges-
tion
(Incidents, Work Zones, Road Weather, and Special Events Traf
c) and the
dissemination of
Traveler Information
about their effects on traf
c congestion were
evaluated and the
findings are summarized below.
Incident Management
was found to be
highly
effective in reducing congestion at
the
local and area
-
wide
scales of impact. It was primarily applied to freeways, and
could be implemented in the
short term
at
low to medium cost
,with
minimum
institutional or regulatory barriers. The potential future effectiveness of incident
management was rated
extensive
(area-wide impacts).
Work Zone
management was
highly
effective in reducing congestion at the
local
scale, was applied in some form in up to 2/3 of the metropolitan areas, and could be
implemented in the
short term
at
low cost
, with
minimum
institutional or regulatory
barriers. The potential future effectiveness of work zone management was rated
moderate
(limited to work zones only).
Road Weather
management had a
medium
effect in reducing congestion at the
local scale of application and a
low
effect at the area-wide scale. The extent of
application in metropolitan areas was
moderate
(up to 2/3 of metropolitan areas use
it), and could be implemented at
low cost,
with
minimum
institutional or regulatory
barriers. The potential future effectiveness in congestion reduction of road weather
management was rated
moderate
(limited to inclement conditions only).
Planned Special Events Traf
c management was
highly
effective at the local
scale of application, was used in about to 2/3 of the metropolitan areas, and could
be implemented at
low cost
with a
medium amount
of institutional or regulatory
