Personal Mobility

This paper is concerned with a study of novel mathematical model of macro-
scopic road network mobility. The approach taken herein is based on the well estab-
lished framework, called cell transmission model (CTM). However, the conventional
CTM (herein called S-CTM) cannot capture the mixed composition of vehicle types
(e.g. truck, car, bus or smaller vehicles), the essence of which is critical to many
applications in practice. CTM is therefore originally generalized into so-called M-
CTM in this paper so as to consider the heterogeneous mobility, i.e. with more than
one class of vehicles. Both S-CTM and M-CTM are compared with the simulated
result in microscopic level from MITSIM software of MIT. The obtained results
suggest that M-CTM is more accurate than S-CTM significantly in uncongested
network with non-stationary vehicle composition without compromising on the
computational complexity. It is therefore expected that the proposed M-CTM would
be well applicable to model large-scale road systems like expressway or highway
systems with heterogenous mixtures of vehicle types.

Chulalongkorn University, Thailand

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York

Congestion on urban freeways, which adversely affects the economy, environment, and quality of life, continues to be a major problem in the United States. Minor incidents, such as minor traffic accidents, stalled vehicles, and special events, account for the majority of urban freeway congestion. Due to the problems associated with freeway incidents, many large metropolitan areas have implemented Incident Management Systems (IMS) to alleviate congestion and safety problems associated with incidents. These systems provide motorists with timely and accurate information to avoid incident locations. Therefore, motorists will experience reductions in travel time and secondary accidents, while increasing speeds and capacity during an incident. Incident management systems have been implemented mainly in large urban areas; however, little is known about the possible benefits in smaller urban areas (second-tier cities).

This study examined the feasibility of implementing IMS in small/medium size urban areas using a case study of the I-29 corridor in Fargo, ND. Due to the lack of knowledge and information regarding the possible benefits of implementing an IMS in smaller urban areas, the evaluation was performed using a simulation model to compare base cases to ITS enhanced cases. The INTEGRATION simulation model was used to estimate the potential benefits of an IMS which employs Advanced Traveler Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS). The study simulated a hypothetical one-lane-blocking incident having a duration of 20 minutes.

The case study analysis revealed that the combination of ATIS and ATMS provided the most favorable network benefits under the 20-minute incident. The IMS reduced incident travel times by 13 percent (city arterials), 28 percent (freeways), and 18 percent (overall network); average trip times were reduced by 20 percent (overall network); and average speeds increased by 21 percent (overall network).

North Dakota State University - Advanced Traffic Analysis Center - Upper Great Plains Transportation Institute

Presented at the 10th ITS Annual Conference and Exposition, May 1-4, 2000 Boston, MA

This paper describes simulation studies on the effect of the inter-vehicle communications on the
improvement of traffic flow along an expressway, and shows the relationship between the
penetration rate of the communication unit and suppression of the shock wave. In the simulation,
20 vehicles are assumed to drive at the same speed of 15 [m/s] and the same headway of 2 [s] or
2.5 [s] along a single lane, and then the lead vehicle slows down with the acceleration of -1 [m/s2]
for 2 [s] and then speeds up with the acceleration of 1 [m/s2] for 2 [s]. If a vehicle is equipped with
a communication unit, it can control the speed without any delay with the data transmitted from a
preceding vehicle to prevent the shock wave to propagate upstream. The simulation results show
that the effective penetration rate of a communication unit is at least 20 % and 10 % for the
headways of 2 [s] and 2.5 [s] respectively.

Department of Information Engineering, Meijo University

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York

It is understood that estimation of travel time on an urban express way is difficult because heaviness  of  congestion  differs  from  day  by  day  and  from  hour  by  hour.  Especially  the accuracy of the estimation gets worse with an external factor of traffic flow theory such as rainfall,  a  fallen  thing  from  a  heavy  truck  on  the  road  and  a  traffic  accident.  The  paper introduces  Bayesian  statistics  to  the  estimation  in  order  to  overcome  the  problem.  From Bayesian theorem a vague prior probability of occurrence of a certain travel time is revised by a  conditional  probability  which is  calculated  as  a joint  probability  of occurrence of  these factors under a certain travel time. The revision accomplishes more accurate estimated travel time from the posterior probability. The paper tries to establish the method in a case study on the MEX (the Metropolitan Expressway) in Tokyo, and an acceptable result is presented.

Pacific Consultants Co., Ltd., Japan

Tokyo University of Science, Japan

Tokyo University of Science

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York

Walking is the most fundamental means of human transportation. Unlike travel by car, human
movement, either on foot or with the aid of a wheelchair, includes vertical movement, using
stairs or elevators, for example. Although there have been amazing developments in car and
outdoor navigation systems, such as EZ-Naviwalk, navigation inside buildings or between tall
buildings is less advanced. We therefore propose a new 3-D positioning system that is driven
primarily by dead reckoning with the support of RFID technology, which can provide realtime
indoor or outdoor position seamlessly. This enables point-to-point ubiquitous navigation
for humans even inside buildings or between tall buildings. In addition, this pedestrian navigation
system can take user’s preferences into account by changing the costs of the road network
link costs in various ways. Altitude differences along the route may be important. For
example, routes having stairs must be avoided by wheelchair-bound users. In addition, timedependent
routing must be considered for indoor navigation. A positioning track accumulation
system is also implemented so that tracks can be stored and their information reflected in
order to incorporate new roads or attributes in the future.

Sophia University

Presented at the 12th World Congress on Intelligent Transport Systems, November 6-10, 2005, San Francisco, California