Bluetooth Applications
Figure 3 - Typical temporary Bluetooth installation
Keeping track Something to get your teeth into
At the present time, tracking of GPS equipped vehicles The University of Maryland and Purdue University have
appears to offer a greater promise of success due to its collaborated in the development of a new technology
ability to provide national coverage at reasonable cost that provides accurate measurement of travel times on
without the need for a cooperating partner. Inrix offers both freeways and arterials. This technology receives
an interesting case study, in that the company has estab- addresses emitted from Bluetooth equipped devices in
lished a national information system of travel time data passing vehicles (cell phones, PDAs, car radios, games,
by using tracking data received from GPS equipped etc.) records their passage time and matches this infor-
fleets. Inrix negotiates contracts with fleet management mation with a second downstream unit.
companies to purchase this data, which is then trans- The difference in passage time between the upstream
lated into speeds and travel times. and downstream units represents the travel time along
The challenge faced by Inrix and its competitors is the the section of roadway on which the two units have been
acquisition of adequate samples of GPS data to provide located. Based on more than 10,000 hours of data col-
reliable information for all types of facilities at all times lection supported by the I-95 Corridor Coalition in con-
of day. Low sample sizes tend to occur during evenings nection with its Vehicle Probe Project, the Bluetooth
and holidays; times when fleet vehicles are in short sup- technology has been shown to provide the ground truth
ply. There are also locations such as tunnels and urban data required for verification of other sources of travel
canyons where GPS satellite signals are unavailable, time.
preventing measurement of travel times and speeds. Perhaps more important, with sample sizes in excess
However, the greatest sample size challenge occurs on of 5 per cent, the Bluetooth technology offers the poten-
signalized arterials, for which larger sample sizes are tial for reliable measurement of traffic flows on arterials.
required due to the variability of this data, while at the The technology is low-cost, low powered and easily
same time fewer samples are available. installed. As a result, it offers costs and capabilities that
While the availability of GPS data is increasing, and exceed those of other methodologies, including con-
with it the accuracy of travel time measurements, it is ventional traffic detection (loops, radar, video, etc.).
likely that these two complimentary issues (fewer fleets Traffax Inc., a new company has been formed under
traveling on arterials and the requirements for larger the auspices of the University of Maryland’s incubator
sample size) will be an impediment to the availability of program, to produce the Bluetooth equipment. The
high quality arterial data for some time to come. Bluetooth electronics and a sample of a portable instal-
As a result, there is a need for a technology that can be lation are shown in Figures 2 and 3 respectively. Traffax
used to supplement the information currently derived has raised the capital needed for commercial produc-
from GPS data. tion of the Bluetooth equipment. It is actively selling this
www.thinkinghighways.com Thinking Highways Vol 4 No 1 37
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68