Global Positioning System Reference
In-Depth Information
Although somewhat inflexible, the RDS-TMC system [1] is very cost-effective
since it can be integrated into the vehicle radio. The advent of digital radio (e.g.,
DAB) is a potentially more flexible approach.
The benefits are simplicity and ubiquity but there is no obvious way to create
a revenue stream other than treating the messages as an attractor to the station to
increase its audience numbers and advertising revenue, if commercial.
The section covering mobile advertising is probably a more likely way for
simple location-dependent information services to progress.
4.2
Dynamic Route Guidance
Route guidance equipment (DRG) is now standard equipment in vehicles based on
GNSS and digital map matching, but it is only recently that the routes suggested
by the route-finding software are becoming able to take into account real-time
information such as unexpected traffic delays.
2
This dynamic approach to route
guidance has been a long time coming and is still primitive in the way it operates.
In the late 1980s and early 1990s there were research programs and projects
3
that showed that DRG could be used for much more than personal guidance, and
could be part of an overall system that could lead to a reduction in overall traffic
congestion and also have potential to manage the environmental impacts. Today,
cellular radio can be used to get simple traffic updates collected by a variety of
methods (e.g., roadside traffic sensors based on cameras or inductive loops buried
beneath the road). The original vision of the experiments is still a valid prospect
and concerns the idea that the vehicles act as traffic probes (collecting what is
sometimes known as floating car data or probe data).
Rather than merely feed back the raw information to other users and thereby
create “rat runs” into inappropriate residential neighborhoods, the experiments
were also about a centralized journey planning system where local traffic
management authorities would dynamically route some traffic one way and others
a different way to balance the road network congestion (using the same body of
theory that communications and Internet data traffic engineers employ). In the
early 1990s the main objective was to save journey times but today and
increasingly in the future, DRG is more likely to be part of a scheme to manage
carbon emissions and perhaps be linked with dynamic road pricing. Urban traffic
management at present is a macroscopic management activity. Accurate vehicle
positioning with integrated mapping, based on an enhanced satellite navigation
unit (or sat-nav) with near real-time communications, could be part of a
microscopic system where the progress and effect of every vehicle are controlled
at all times, or at least in important urban areas.
2
Chapter 8 has details and references of some service providers using Web 2.0 for mapping and route
sat-nav manufacturers such as TomTom who add dynamic services to basic stand-alone products.
3
IVHS America (Intelligent Vehicle Highway Systems) in the United States and DRIVE, part of the
EU's Second Framework Research Programme.
