In reduced speed zones, where no other cues indicate the need to slow down, drivers sometimes fail to notice the standard Speed Limit sign and may be speeding inadvertently. To help reduce inadvertent speeding, a red border was installed around the Speed Limit sign in seven reduced speed areas and the impacts of the increased conspicuity on speed limit compliance were measured. The general study approach was to collect and compare speed data for a standard sign (before condition) and a red border sign (after condition). The short-term effects of a modified red border sign, which was achieved by replacing the thin black border of the standard sign with a four inch wide red border, were evaluated at four sites. Results of this modified border study indicated that there was a statistically significant reduction in the mean speeds as well as in the 85th percentile speeds for the red border sign conditions, however the reductions were not practically significant. This study also evaluated the effect of using a higher conspicuity sheeting material at two sites. The results indicated that use of higher conspicuity sheeting has some benefits for the standard sign but no additional benefits for the red border sign. The added border study evaluated the long-term effects (approximately nine to eleven months after the treatment) of adding a three inch wide red border to the standard Speed Limit sign at three sites. The results of this study indicated that impacts of the red border treatment increase with passage of time. The mean speeds decreased by 8.1 percent and the percent of vehicles exceeding the speed limit (55 mph) decreased by 21.7 percent. The decreases in speeds were both statistically and practically significant. A comparison of the thesis study with other similar studies found in literature shows comparable benefits of the red border sign with other speed management measures. Based on the results for long-term effects, use of the red border Speed Limit sign is recommended in reduced speed zones where inadvertent speeding is common.

In reduced speed zones, where no other cues indicate the need to slow down, drivers sometimes fail to notice the standard Speed Limit sign and may be speeding inadvertently. To help reduce inadvertent speeding, a red border was installed around the Speed Limit sign in seven reduced speed areas and the impacts of the increased conspicuity on speed limit compliance were measured. The general study approach was to collect and compare speed data for a standard sign (before condition) and a red border sign (after condition). The short-term effects of a modified red border sign, which was achieved by replacing the thin black border of the standard sign with a four inch wide red border, were evaluated at four sites. Results of this modified border study indicated that there was a statistically significant reduction in the mean speeds as well as in the 85th percentile speeds for the red border sign conditions, however the reductions were not practically significant. This study also evaluated the effect of using a higher conspicuity sheeting material at two sites. The results indicated that use of higher conspicuity sheeting has some benefits for the standard sign but no additional benefits for the red border sign. The added border study evaluated the long-term effects (approximately nine to eleven months after the treatment) of adding a three inch wide red border to the standard Speed Limit sign at three sites. The results of this study indicated that impacts of the red border treatment increase with passage of time. The mean speeds decreased by 8.1 percent and the percent of vehicles exceeding the speed limit (55 mph) decreased by 21.7 percent. The decreases in speeds were both statistically and practically significant. A comparison of the thesis study with other similar studies found in literature shows comparable benefits of the red border sign with other speed management measures. Based on the results for long-term effects, use of the red border Speed Limit sign is recommended in reduced speed zones where inadvertent speeding is common.

Master of Science / Department of Civil Engineering / Sunanda Dissanayake / In the United States, the mileage of unpaved roads is about 1.6 million miles. Total length of unpaved roads in Kansas is about 98,000 miles, of which about 78,000 miles are gravel roads. Most of the gravel roads are not posted with speed limit signs but regulated with a 55 mph blanket speed limit established by the Kansas Statutes. Surface conditions of gravel roads are very likely to change with time, space, and quality of maintenance work, making it even more necessary to have proper control of speeds on gravel roads. Normally used speed regulations and rules for freeways or other types of paved roadways might not be appropriate for gravel roads, especially for those local gravel roads which usually carry very low traffic in rural areas. Based on an extensive literature search, there was no specific rule or references to provide guidelines on how speed limits on gravel roads could be set. Therefore, an effort was made in this study to evaluate the effects of currently posted lower speed limits in some counties in Kansas, based on traffic characteristics and safety on gravel roads, with the intention of providing proper guidelines for setting speed limits on gravel roads in Kansas. In order to study traffic characteristics on gravel roads, field speed studies were conducted with automatic traffic counters on more than forty gravel road sections in seven counties in Kansas. Important speed measures, such as 85th-percentile speed and mean speed, were obtained from the raw data. A group of other related road characteristics were also recorded at the time of field data collection. Crash data on gravel roads were extracted from the Kansas Accident Recording System (KARS) database. Speed analysis on a number of gravel roads where the statutory imposed, unposted speed limit of 55 mph was utilized indicated that they are functioning at a reasonably acceptable level in terms of actual speeds. In order to evaluate whether there were differences in traffic speeds between two counties or groups which have different speed limit settings on gravel roads, t-test was used. The analysis found that there was no significant difference between the mean speeds in two counties, one of which has 35 mph posted speed limit on gravel roads while the other does not post any speed limits. Moreover, the mean speed on the sections with 35 mph posted speed was a little higher than that on gravel roads without any speed limits. Linear models to predict 85th-percentile speed and mean speed on gravel roads were developed based on speed data. Both models indicated that traffic speeds are not significantly affected by the speed limit, but are related with 90% confidence to road width, surface classification and percentage of large vehicles in traffic. Chi-square tests were conducted with the crash data, and the results indicated that the posted 35 mph speed limit on gravel roads had not resulted in either smaller total number of crashes or decreased proportion of severe crashes, compared to gravel roads where no speed limits were posted. Logistic regression models were also developed on four levels of crash severity, which indicated that gravel roads with higher speed limits are likely to experience higher probability of having injury crashes. Two mail-back surveys were also conducted to gather the opinions of county engineers and road users on the subject of suitable speed limits on gravel roads. The majority of county engineers believed that blanket speed limit should be used for gravel roads and does not need to be posted. Three restrictions: changeful road conditions, unpractical law enforcement, and limited funds, are basic reasons why they do not think that gravel roads should be posted. Besides that, a few respondents said 55 mph is too high for gravel roads and needs to be lowered. Majority of the road users suggested that all gravel roads be posted with lower speed limit signs. However, they were more concerned about law enforcement since they believe that posted speeds won't bring any benefits if no law enforcement patrol gravel roads. Based on all aspects looked into in this study, it does not appear that reducing the speed limits and posting it with signs, is going to improve either traffic operational or safety characteristics on gravel roads in Kansas, and therefore is not recommended for new situations.

Variable speed limit (VSL) systems are important active traffic management tools that are being deployed across the U.S. and indeed around the world for relieving congestion and improving safety. Oregon’s first variable advisory speed limit signs were activated along Oregon Highway 217 in the summer of 2014. The variable advisory speed system is responsive to both congestion and weather conditions. This seven-mile corridor stretches around Western Portland and has suffered from high crash rates and peak period congestion in the past. VSL systems are often deployed to address safety, mobility and sustainability related performance. This research seeks to determine whether the newly implemented variable advisory speed limit system has had measurable impacts on traffic safety and what the scale of the impact has been. The research utilizes a before-after crash analysis with three years of data prior to implementation and around 16 months after. Statistical analysis using an Empirical Bayes (EB) approach will aim to separate the direct impacts of the variable advisory speed limit signs from the long term trends on the highway. In addition, the analysis corrects for the changes in traffic volumes over the study period. Three data sources will be utilized including Washington County 911 call data, Oregon incident reports, and official Oregon Department of Transportation crash data reports. The analysis results are compared between data sources to determine the reliability of 911 call data as a proxy for crash statistics. The conclusions should be able to provide an indication of whether variable advisory speed limits can provide increased safety along high crash corridors.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Accompanying cassette titled: Radar field test. / Bibliography: leaf 18. / by Allen Yee. / B.S.

Since last two decades researches have been working on developing systems that can assistsdrivers in the best way possible and make driving safe. Computer vision has played a crucialpart in design of these systems. With the introduction of vision techniques variousautonomous and robust real-time traffic automation systems have been designed such asTraffic monitoring, Traffic related parameter estimation and intelligent vehicles. Among theseautomatic detection and recognition of road signs has became an interesting research topic.The system can assist drivers about signs they don’t recognize before passing them.Aim of this research project is to present an Intelligent Road Sign Recognition System basedon state-of-the-art technique, the Support Vector Machine. The project is an extension to thework done at ITS research Platform at Dalarna University [25]. Focus of this research work ison the recognition of road signs under analysis. When classifying an image its location, sizeand orientation in the image plane are its irrelevant features and one way to get rid of thisambiguity is to extract those features which are invariant under the above mentionedtransformation. These invariant features are then used in Support Vector Machine forclassification. Support Vector Machine is a supervised learning machine that solves problemin higher dimension with the help of Kernel functions and is best know for classificationproblems.

During last decades, the Internet teleobotics has been growing at an enormous ratedue to the rapid improvement of Internet technology. This paper presents theinternet-based remote control of mobile robot. To face unpredictable Internet delaysand possible connection rupture, a direct continuous control based teleoperationarchitecture with “Speed Limit Module” (SLM) and “Delay Approximator” (DA) isproposed. This direct continuous control architecture guarantees the path error of therobot motion is restricted within the path error tolerance of the application.Experiment results show the feasibility and effectiveness of this direct Internet controlarchitecture in the real Internet environment.

In this research the problem of incident congestion on surface street networks is addressed. Microscopic simulation is used to simulate incident scenarios on various corridors in the Tampa Bay area. The effect of the three factors, namely, network, speed and signal strategies on the traffic flow is studied. The network performance is based on Highway Capacity Manual specified measures of effectiveness prepared by the Transportation Research Board. Three inherently different city corridors, high, medium and low volume, are used to test the strategies developed. The strategies investigated include varying speed limits during incidents and using pre-timed and semi-actuated signals that respond to real time traffic volumes. The effectiveness measures are total delay in vehicle minutes, average speed in miles per hour and average travel time in seconds. Different facilities on a network include intersections; both signalized and unsignalized, local highways and arterials. The outputs from the simulation model is used to set up a factorial design to study the interaction between network type, signal strategy and speed strategy with the measures of effectiveness being the response variables. This type of corridor analysis is unique and provides decision support for local transportation planning departments for making corridor enhancements. In most city, state or county planning departments road planning is merely based on projected traffic demand using existing static models and does not factor necessary adjustments for incidents. Another unique aspect of this research is that variable speed limits are tested on surface streets. Such a test is not available in the literature. With dynamic message signs, next generation communication networks for traffic signal control and ITS technologies available, it is possible to implement the strategies suggested in this research.

A velocidade elevada e a sua variabilidade são consideradas fatores determinantes na causa de acidentes e gravidade dos mesmos. A freqüência dos acidentes decresce quando os limites de velocidade estabelecidos são apropriados ou realísticos. O limite estabelecido deve estar de acordo com as velocidades praticadas pela média dos condutores ditos prudentes, ou este limite não será considerado. No presente estudo é elaborado um método para estabelecimento de limites de velocidade básicos para rodovias de pista simples do Estado do Rio Grande do Sul. O método parte das velocidades operacionais da via e de seus graus de mobilidade e acessibilidade, sugerindo um limite de velocidade único para os dois sentidos da via. Também são sugeridas velocidades de advertência em curvas do alinhamento horizontal. Seis rodovias do Estado do Rio Grande do Sul foram selecionadas para um estudo de caso. A seleção procura englobar rodovias de classes de projeto e região diferentes, para que se possa fazer uma análise ampla de projetos de rodovias. As rodovias, a partir de suas velocidades operacionais e dados de geometria, têm seus limites de velocidade calculados. Na seqüência, as velocidades de advertência são calculadas. Os resultados são apresentados em forma de gráficos para facilitar a compreensão da distribuição das velocidades ao longo da extensão do trecho. Os resultados de cada trecho são analisados e comparados. / High speed and its variability are considered determining factors in the cause of accidents and its severity. The frequency of accidents decreases when the speed limits established are appropriate or realistic. The limit must be established in accordance with the speeds practiced by the average conservative drivers, or this limit will not be considered. In the present study a method is developed to establish basic speed limits for two-lane highways of the state of Rio Grande do Sul. The method relies on the operational speed of the track and its degrees of mobility and accessibility, suggesting one speed limit for both ways of the road. It is also suggested warning speeds for curves in the horizontal alignment. Six two-lane highways of the state of Rio Grande do Sul were selected for a case study. The selection was made so all classes of project and different regions were included, in a way that analysis of different projects could be done. The two-lane highways have their limits of speed calculated, from their operating speeds and geometry data. Next, the warning speeds are calculated. The results are presented in the form of graphs to facilitate the understanding of the distribution of velocities along the length of the segment. The results of each different segment are analyzed and compared.

A velocidade elevada e a sua variabilidade são consideradas fatores determinantes na causa de acidentes e gravidade dos mesmos. A freqüência dos acidentes decresce quando os limites de velocidade estabelecidos são apropriados ou realísticos. O limite estabelecido deve estar de acordo com as velocidades praticadas pela média dos condutores ditos prudentes, ou este limite não será considerado. No presente estudo é elaborado um método para estabelecimento de limites de velocidade básicos para rodovias de pista simples do Estado do Rio Grande do Sul. O método parte das velocidades operacionais da via e de seus graus de mobilidade e acessibilidade, sugerindo um limite de velocidade único para os dois sentidos da via. Também são sugeridas velocidades de advertência em curvas do alinhamento horizontal. Seis rodovias do Estado do Rio Grande do Sul foram selecionadas para um estudo de caso. A seleção procura englobar rodovias de classes de projeto e região diferentes, para que se possa fazer uma análise ampla de projetos de rodovias. As rodovias, a partir de suas velocidades operacionais e dados de geometria, têm seus limites de velocidade calculados. Na seqüência, as velocidades de advertência são calculadas. Os resultados são apresentados em forma de gráficos para facilitar a compreensão da distribuição das velocidades ao longo da extensão do trecho. Os resultados de cada trecho são analisados e comparados. / High speed and its variability are considered determining factors in the cause of accidents and its severity. The frequency of accidents decreases when the speed limits established are appropriate or realistic. The limit must be established in accordance with the speeds practiced by the average conservative drivers, or this limit will not be considered. In the present study a method is developed to establish basic speed limits for two-lane highways of the state of Rio Grande do Sul. The method relies on the operational speed of the track and its degrees of mobility and accessibility, suggesting one speed limit for both ways of the road. It is also suggested warning speeds for curves in the horizontal alignment. Six two-lane highways of the state of Rio Grande do Sul were selected for a case study. The selection was made so all classes of project and different regions were included, in a way that analysis of different projects could be done. The two-lane highways have their limits of speed calculated, from their operating speeds and geometry data. Next, the warning speeds are calculated. The results are presented in the form of graphs to facilitate the understanding of the distribution of velocities along the length of the segment. The results of each different segment are analyzed and compared.