Short-Term Evaluation of Transition from Differential to Uniform Speed Limit for Trucks and Buses on Two-Lane Highways

2017 ◽  
Vol 2637 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Raha Hamzeie ◽  
Bijan Vafaei ◽  
Jonathan J. Kay ◽  
Peter T. Savolainen ◽  
Timothy J. Gates
Keyword(s):  
Field Studies ◽  
Speed Limit ◽  
Short Term ◽  
Immediate Feedback ◽  
Speed Limits ◽  
Rural Highways ◽  
Short Term Evaluation ◽  
Term Evaluation ◽  
Operational Issues ◽  
Differential Speed

As of November 2016, Montana was the only state to maintain a differential speed limit on two-lane two-way rural highways, with a daytime statutory speed limit of 70 mph for cars and light trucks and 60 mph for trucks exceeding a 1-ton payload capacity. Although differential speed limits are common on freeways, the use of differential limits on two-lane roadways presents unique safety and operational issues because of passing limitations and the resultant platooning that occurs. Given these concerns, the speed limit was changed from the differential 70 mph to 60 mph speed limit to a uniform 65 mph limit for all vehicles along 55 mi of two-lane highway in April 2013. This study evaluated the short-term operational and safety impacts associated with this transition. Given the limited time period over which data were available following the speed limit change, surrogate safety measures were investigated to provide immediate feedback as to these impacts. A series of field studies was performed on two-lane rural highways in Montana, which predominantly possessed the 70 mph to 60 mph differential speed limit, as well as on selected locations along the 55 mi where the uniform speed limit was implemented. The locations with 65 mph speed limits generally exhibited shorter platoon lengths and less high-risk passing behavior. Overall, the preliminary findings provide some general support for transitioning to a uniform 65 mph speed limit on two-lane rural highways.

Setting Speed Limits on Kansas Two-Lane Highways: Neuronet Approach

2000 ◽  
Vol 1708 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Yacoub M. Najjar ◽  
Robert W. Stokes ◽  
Eugene R. Russell
Keyword(s):  
Neural Network ◽  
Back Propagation ◽  
Field Studies ◽  
Back Propagation Neural Network ◽  
Speed Limit ◽  
Speed Limits ◽  
Rural Highways ◽  
Resource Limitations ◽  
Traffic Volumes ◽  
The Relationship

Recent federal legislation allowing states to set their own speed limits on highways, as well as increases in the number of requests from citizens and neighborhood groups to implement actions to reduce “excessive” speeding on their streets and highways, has created considerable debate about and scrutiny of the appropriate speed limits that should be posted on state highways. Various speed studies have indicated that sensible and cautious drivers will most likely drive at the speed dictated by roadway and traffic conditions rather than relying on a posted speed limit. To incorporate roadway characteristics and traffic volumes into the selection of the most appropriate (i.e., comfortable, safe, and efficient) speed limit, actual engineering field speed studies are carried out. Generally, the 85th percentile speed at which the drivers surveyed are driving is selected as a primary factor in determining the posted speed limit. Carrying out such field studies for all highway sections is a costly and time-consuming process. Therefore, characterizing the relationship between the 85th percentile speed and the roadway characteristics will assist in selecting the most appropriate posted speed limit on highway sections where field surveying is difficult due to resource limitations. A back-propagation neural network is used to extract the relationship between roadway characteristics and 85th percentile speed. The developed neural-network-based speed model was found to perform satisfactorily for characterization of speed on Kansas two-lane, uninterrupted-flow rural highways and for quantifying the influence of prevailing roadway characteristics on the anticipated 85th percentile speed.

scholarly journals Evaluating the Impacts of Speed Limit Increases on Rural Two-Lane Highways Using Quantile Regression

2021 ◽  
pp. 036119812110197
Author(s):  
Md Shakir Mahmud ◽  
Nischal Gupta ◽  
Babak Safaei ◽  
Hisham Jashami ◽  
Timothy J. Gates ◽  
...  
Keyword(s):  
Quantile Regression ◽  
Spillover Effects ◽  
Speed Limit ◽  
Passenger Cars ◽  
Cross Sectional ◽  
Speed Limits ◽  
Site Specific ◽  
Rural Highways ◽  
Speed Selection ◽  
Numerous Site

Understanding speed selection behavior of drivers following speed limit increases is critically important. To date, the literature has largely focused on freeways and the effects of speed limit changes on two-lane highways remains under researched. Prior research has generally focused on changes to mean speeds, although the speeds of both the highest and lowest drivers are also of great interest. This study investigates trends in free-flow travel speeds following 2017 legislation that increased the posted speed limit from 55 to 65 mph on 943 mi of rural highways in Michigan. Speed data were collected for over 46,000 drivers at 67 increase segments where speed limit increased and 28 control segments where speed limits remained unchanged, before and during each of the two successive years following the speed limit increases. Site-specific traffic, geometric, and cross-sectional information was also collected. Impacts of the speed limit increases on the 15th, 50th, and 85th percentile speeds were evaluated using quantile regression. Separate analyses were conducted for passenger cars and heavy vehicles. Locations where the speed limits were raised experienced increases in travel speeds ranging from 2.8 to 4.8 mph. The control sites experienced marginal changes in speeds, which suggests that any spillover effects of the higher speed limits have been limited. Significant differences were observed across the quantiles with respect to the effects of the speed limit increases, as well as numerous site-specific variables of interest. The results provide important insights about the nature of driver speed selection and the impacts of speed limit increases.

scholarly journals Short-term Evaluation of Synovectomy in Haemophilia

BMJ ◽  
1972 ◽  
Vol 2 (5810) ◽  
pp. 378-381 ◽  
Author(s):  
V. Pietrogrande ◽  
N. Dioguardi ◽  
P. M. Mannucci
Keyword(s):  
Short Term ◽  
Short Term Evaluation ◽  
Term Evaluation

Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities

2003 ◽  
Vol 19 (8) ◽  
pp. 739-746 ◽  
Author(s):  
Carlos Alberto de Souza Costa ◽  
Elisa Maria Aparecida Giro ◽  
Alexandre Batista Lopes do Nascimento ◽  
Hilcia Mezzalira Teixeira ◽  
Josimeri Hebling
Keyword(s):  
Glass Ionomer Cement ◽  
Bonding Agent ◽  
Glass Ionomer ◽  
Short Term ◽  
Complex Response ◽  
Resin Modified Glass Ionomer ◽  
Short Term Evaluation ◽  
Term Evaluation ◽  
Deep Cavities ◽  
Ionomer Cement

scholarly journals Efficacy of a bystander intervention for preventing dating violence in Brazilian adolescents: short-term evaluation

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Karine Brito dos Santos ◽  
Sheila Giardini Murta ◽  
Luis Gustavo do Amaral Vinha ◽  
Juliana Silva de Deus
Keyword(s):  
Romantic Relationships ◽  
Dating Violence ◽  
Control Group ◽  
Short Term ◽  
Brazilian Sample ◽  
Post Test ◽  
Short Term Evaluation ◽  
Term Evaluation ◽  
Brazilian Culture

Abstract Peers are the preferred source of help for Brazilian adolescents who experience dating violence. However, they are not always the best informants for effective responses for dealing with situations of violence in romantic relationships among peers. This experimental study aimed to evaluate the short-term efficacy of three aspects of a peer- and bystander approach-based intervention: the intent to offer help, empathy, and bystander attitudes in response to dating violence in a Brazilian sample of adolescents. The study’s participants were 33 adolescents randomized in two groups: experimental group (EG, n = 14) and control group (CG, n = 19). The EG underwent three weekly intervention sessions of 90 min each on the healthy versus violent romantic relationships, the quality of friendship in the peer network, and the role of the bystander, while the CG received no intervention. Evaluations were performed 1 week before and two and half months after the intervention. Statistically significant differences between EG and CG at post-test were not found in intention to help, empathy, and bystander attitudes. Future studies should include evaluations of larger samples and mid- and long-term follow-ups to identify patterns of change over the long term as well as examine barriers to utilization of bystander behaviors by adolescents in Brazilian culture.

scholarly journals A short-term evaluation of a hospital no hit zone policy to increase bystander intervention in cases of parent-to-child violence

2018 ◽  
Vol 94 ◽  
pp. 155-162 ◽  
Author(s):  
Elizabeth T. Gershoff ◽  
Sarah A. Font ◽  
Catherine A. Taylor ◽  
Ann Budzak Garza ◽  
Denyse Olson-Dorff ◽  
...  
Keyword(s):  
Bystander Intervention ◽  
Short Term ◽  
Short Term Evaluation ◽  
Term Evaluation ◽  
Child Violence

scholarly journals Immediate loading over lower prosthesis in edentulous mandibles: comparison between two types of prosthetic connection

2017 ◽  
Vol 65 (4) ◽  
pp. 308-314
Author(s):  
Marina Reis OLIVEIRA ◽  
Ariane de Souza OLIVEIRA ◽  
Vitor Augusto LEITE ◽  
Marisa Aparecida Cabrini GABRIELLI ◽  
Oriana Elara Barelli PAGANELLI ◽  
...  
Keyword(s):  
Immediate Loading ◽  
Viable Option ◽  
Short Term ◽  
Significance Level ◽  
Implant Stability Quotient ◽  
Probing Depth ◽  
Significant Difference ◽  
Implant Abutment ◽  
Short Term Evaluation ◽  
Term Evaluation

ABSTRACT Objective: This study evaluated two implant-abutment connection systems under immediate loading of lower prosthesis in edentulous mandibles. Methods: Seventy-two implants placed in 18 patients were analyzed. The parameters evaluated included probing depth, stability of implants and perimplant bone loss, which were measured immediately when installing the prosthesis and after 3 and 6 months. All data underwent statistical analysis (T-Test and ANOVA, 5% significance level). Results: Implants with Morse cone connections showed smaller, statistically significant probing depth values for all periods (0.68/1.19/1.31), when compared to the external hexagon connections (1.08/1.52/1.64). A statistically significant difference was observed between baseline, 3 months (p<0.01 for Morse cone; p<0.001 for external hexagon) and 6 months (p<0.001 for both connections). When periods were considered there was a statistically significant difference in Implant Stability Quotient ISQ values between baseline and 6 months for both prosthetic connections. Conclusion: Immediate loading of the lower prosthesis is a viable option for the treatment of edentulous mandibles and that the external hexagon or Morse cone connections do not interfere with the success of the implants in a short-term evaluation.

Sign in / Sign up

Export Citation Format

Share Document