Showing papers by "California Department of Transportation published in 2005"
TL;DR: It is speculated that the significant differences between rural and urban injury severities may be at least partially attributable to the different perceptual, cognitive and response demands placed on drivers in rural versus urban areas.
332 citations
TL;DR: The earliest evidence for long-distance trade in western North America dates to at least 10,300 and 10,000 years BP as mentioned in this paper, with an AMS date between 11,200 and 7860.
57 citations
TL;DR: A real-time laser-based nonintrusive detection system has been developed for the measurement of true travel time of vehicles on the highway and the results indicate that the laser system operates well under real highway conditions.
Abstract: A real-time laser-based nonintrusive detection system has been developed for the measurement of true travel time of vehicles on the highway. The detection system uses a laser line that is projected onto the ground as a probe. The reflected light is collected and focused into a photodiode array by an optical system. Vehicle presence is detected based on the absence of reflected laser light. By placing two identical laser/sensor pairs at a known distance apart, the speeds of both the front and rear of a vehicle are measured based on the times when each sensor is triggered. The length of each vehicle is determined by using these speed measurements and the residence time of the vehicle under each sensor. Using real-time software, the speed, acceleration, and length of a detected vehicle can be calculated and displayed simultaneously. A new prototype system has been tested on the highway with different types of vehicles and scenarios, and the results are presented here. The tests have also been carried out for different weather conditions and road materials. The results indicate that the laser system operates well under real highway conditions.
39 citations
TL;DR: In this article, a preliminary analysis was performed on the California data set, to quantify the deterioration transition probabilities actually observed, and to determine whether it is yet possible to validate the key assumptions of Markovian bridge deterioration models.
Abstract: Markovian bridge deterioration models have been in use in the United States since the early 1990s, using the AASHTO Guide to Commonly-Recognized Structural Elements. California has one of the oldest databases of inspection history using this standard. A preliminary analysis was performed on the California data set, to quantify the deterioration transition probabilities actually observed, and to determine whether it is yet possible to validate the key assumptions of Markovian bridge deterioration models. Several important conclusions were reached, which should provide guidance for future research and implementation.
38 citations
TL;DR: In this paper, the authors present an alternative to other methods of analysis, e.g., Abrahamson (2000) [Abrahamson, N.A., 2000] and this paper.
35 citations
TL;DR: This paper introduces an innovative approach to development of construction and traffic management plans for the I-15 Devore project, a fast-track urban freeway reconstruction project with high traffic volume in Southern California by integrating construction schedule, traffic delay, and agency cost.
Abstract: This paper introduces an innovative approach to development of construction and traffic management plans for the I-15 Devore project, a fast-track urban freeway reconstruction project with high traffic volume in Southern California. The goal of this approach is to determine the most economical reconstruction closure scenario by integrating construction schedule, traffic delay, and agency cost. Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software was used for scheduling analysis. The demand-capacity model based on the Highway Capacity Manual, and macroscopic and microscopic traffic simulation models were utilized for traffic delay analysis. Based on these analyses, the California Department of Transportation decided to implement eight 72 h weekday closures with round-the-clock operations for this reconstruction project. This was found to be more beneficial for both the agency and the traveling public than the alternative of: (1) 55 h weekend, (2) 10 h nighttime, or (3) one-time co...
31 citations
TL;DR: In this article, a pre-construction analysis of the fast-track pavement reconstruction on Interstate-15 (I-15) at Devore which used two one-roadbed continuous (about 210 hours) closures with round-the-clock (24/7) operations is presented.
Abstract: The California Department of Transportation is rehabilitating or reconstructing deteriorated urban freeways using long-life (30+ years) strategies. These pavements were constructed between 1955 and 1970 with design lives of 20 years. This paper summarizes pre-construction analysis of the fast-track pavement reconstruction on Interstate-15 (I-15) at Devore which used two one-roadbed continuous (about 210 hours) closures with round-the-clock (24/7) operations. The integrated analysis concluded that the one-roadbed continuous closures are the most economical scenario when compared to traditional nighttime or weekend closures from the perspective of schedule, delay, and costs. The pre-construction was validated with as-built construction and traffic performances monitored during construction. The construction management plan – including contingency, incentives, and CPM schedule – was developed utilizing the Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) computer model. The results of this planning study are useful for transportation agencies in developing highway rehabilitation strategies that balance the maximization of construction productivity with a minimization of traffic delay.
23 citations
TL;DR: An integrated approach to the development of construction and traffic management plans for the reconstruction of high-volume urban freeways is introduced and full closure of one roadbed with counter-flow traffic during repeated three or four continuous weekdays, utilizing round-the-clock reconstruction operations, was the best strategy for both the public and the sponsoring agency.
Abstract: This paper introduces an integrated approach to the development of construction and traffic management plans for the reconstruction of high-volume urban freeways. The Devore project, which rebuilds a 4.2 km stretch of the deteriorated concrete pavement (truck lanes) on Interstate-15 (I-15) in San Bernardino County in southern California, is used as a case study. Alternative closure timing, closure duration, and number of closed lanes were compared to identify the best rehabilitation strategy for the Devore reconstruction project. The perspectives of construction schedule, traffic inconvenience (road user cost and maximum delay), and agency costs were considered. The analysis concluded that full closure of one roadbed with counter-flow traffic during repeated three or four continuous weekdays, utilizing round-the-clock reconstruction operations, was the best strategy for both the public and the sponsoring agency. A delay in the start of construction from Spring to Fall 2004 is expected to cause a 5% seasonal traffic increase, which will result in a $4.5 million increase in road user cost and a 20% increase in maximum queue delay per closure.
20 citations
TL;DR: In this article, aerial photographs from 1928, 1945, 1975, and 1994 were acquired for San Dieguito Lagoon, in San Diego County, California, USA, to analyze change of a coastal wetland using remote sensing, image processing, and GIS techniques.
Abstract: This study analyzed change of a coastal wetland using remote sensing, image processing, and GIS techniques. Aerial photographs from 1928, 1945, 1975, and 1994 were acquired for San Dieguito Lagoon, in San Diego County, California, USA. The photographs were scanned and the landscape classified as wetland or non-wetland. A GIS model quantified and indicated trends in wetland change. Results show that, in 1928, 50% (366 ha) of the study area was comprised of wetlands. By 1994, the total wetland area decreased to 15% (109 ha) of the study site area. The annualized loss reveals a continual decrease in the rate of loss over all three time periods, which corresponds to the national decline in the rate of wetland loss. The greatest loss rate occurred from 1928 to 1945 (3% per year), and the lowest rate of loss occurred from 1975 to 1994 (0.3% per year).
19 citations
TL;DR: For all of the eight freeway segments evaluated, it was found that the mean absolute percentage errors of estimated delay are consistently less than 7%, when delay is defined using a reference speed higher than 60 mph (96 kmph).
19 citations
TL;DR: The program was developed as a scheduling and production analysis tool for LLPRS projects for use during the planning and design stages and estimates the optimized distance and duration of highway rehabilitation projec...
Abstract: Most of California's highway infrastructure was built between 1955 and 1970. These pavements had 20-year design lives, and many now require frequent maintenance. In 1998, the California Department of Transportation (Caltrans) launched the Long-Life Pavement Rehabilitation Strategies (LLPRS) program to rebuild approximately 2,800 lane kilometers of high-traffic-volume urban freeway in the 78,000-lane kilometer state highway network over a 10-year period. Priorities identified for the successful implementation of LLPRS projects are the selection of construction schedules and the development of traffic management plans that minimize road user and agency costs. This paper presents a construction simulation program called CA4PRS (Construction Analysis for Pavement Rehabilitation Strategies). The program was developed as a scheduling and production analysis tool for LLPRS projects for use during the planning and design stages. CA4PRS estimates the optimized distance and duration of highway rehabilitation projec...
TL;DR: In this article, the first asphalt concrete (AC) project for the Long-Life Pavement Rehabilitation Strategies (LLPRS) program is presented, where a 4.4km stretch of deteriorated concrete pavement on I-710 in Long Beach was rehabilitated successfully with 230 mm of AC overlay or 325 mm of full-depth AC replacement during eight 55-h weekend closures.
Abstract: Rehabilitation of urban highways is a critical issue confronting the California Department of Transportation because the state has a significant inventory of overaged, heavily trafficked urban highways showing extensive signs of distress. This paper presents the innovative pavement rehabilitation technologies and techniques that the agency applied in the first asphalt concrete (AC) project for its Long-Life Pavement Rehabilitation Strategies (LLPRS) program. A 4.4-km stretch of deteriorated concrete pavement on I-710 in Long Beach was rehabilitated successfully with 230 mm of AC overlay or 325 mm of full-depth AC replacement during eight 55-h weekend closures. The pilot project proved that the accelerated (fast-track) rehabilitation with 55-h weekend closures is a viable option that can drastically shorten the overall construction time and lessen the negative effects of construction in an urban area. The project also proved that AC pavement designed to provide a design life of 30-plus years can be constru...
TL;DR: Experimental results from field tests show that the application of the real-time architecture to theLBDS provides vehicle parameter calculations deterministically, and a method to collect hard real- time signals from an active laser source in the LBDS and calculate real-Time vehicle parameters using a standard computer is provided.
Abstract: A three layer real-time architecture for a highway vehicle detection system is presented in the article. The Laser-Based Detection System (LBDS), focused on helping the Intelligent Transportation System (ITS), measures a key quantitative parameter of vehicles moving across a link of highway, namely, travel time. Travel time is based upon identifying and re-identifying vehicles at various points on the highway. This article provides a method to collect hard real-time signals from an active laser source in the LBDS and calculate real-time vehicle parameters using a standard computer. A method of seamlessness message exchange between a hard real-time kernel process, for real-time data acquisition, and a soft real-time application process, for computing and displaying, is given under the RTLinux environment. Experimental results from field tests show that the application of the real-time architecture to the LBDS provides vehicle parameter calculations deterministically. Experimental data are analyzed using the Video Sync program with both video images and graphical display.
TL;DR: In this paper, the authors propose a method to solve the problem of homonymity of homophily in the context of homomorphic data, and no abstracts are available.
Abstract: No abstract available.
01 Jan 2005
TL;DR: In this article, a digitally-controlled optimal self-calibration method for laser-photodiode-based vehicle detection system (LBDS) is presented, which is based on projecting laser beams to the road and receiving the echo laser.
Abstract: The Laser-photodiode Based vehicle Detection System (LBDS) is an advanced vehicle detector. Its detection principle is based on projecting laser beams to the road and receiving the echo laser. When the operation environment such as the road surface condition, the weather and the daylight changes, which is likely to happen over the long-term lifespan of the LBDS, the LBDS may require recalibration. To solve this problem, a digitally-controlled optimal self-calibration method for LBDS is presented in the paper. With the calibration, the LBDS has the ability to operate reliably in a wide range of applications, and has the ability to provide correct and accurate detection information over the long term. The field test results of the LBDS using the proposed self-calibration method confirm the effectiveness of the self-calibration method.Copyright © 2005 by ASME