Emissions Impact of Eliminating National Speed Limits: One Year Later

The National Highway System (NHS) bill passed by Congress in November 1995 eliminated the national maximum speed limit. It has allowed states to set their own speed limits, which many have changed during the past year. This analysis examines the impact of speed limit changes 1 year after passage of the NHS. Oxides of nitrogen (NOx), carbon monoxide, and volatile organic compounds are analyzed and are found to have increased nationwide by up to 6, 7, and 2 percent, respectively. Much of the increase has occurred in western states, which generally have increased vehicle speeds more than in eastern and midwestern states. For example, in Texas NOx emissions are estimated to have increased by 35 percent due to large increases in highway and arterial speed limits.

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The Geometry of Speed Limiting Resources in Physical Models of Computation

International Journal of Foundations of Computer Science ◽

10.1142/s0129054117500204 ◽

2017 ◽

Vol 28 (04) ◽

pp. 321-333 ◽

Cited By ~ 5

Author(s):

Benjamin Russell ◽

Susan Stepney

Keyword(s):

Limited Resource ◽

Minimum Time ◽

Physical Models ◽

Maximum Speed ◽

Speed Limit ◽

Physical Computation ◽

Speed Limits ◽

Models Of Computation ◽

Special Cases ◽

Time Optimal

We study the maximum speed of quantum computation and how it is affected by limitations on physical resources. We show how the resulting concepts generalize to a broader class of physical models of computation within dynamical systems and introduce a specific algebraic structure representing these speed limits. We derive a family of quantum speed limit results in resource-constrained quantum systems with pure states and a finite dimensional state space, by using a geometric method based on right invariant action functionals on [Formula: see text]. We show that when the action functional is bi-invariant, the minimum time for implementing any quantum gate using a potentially time-dependent Hamiltonian is equal to the minimum time when using a constant Hamiltonian, thus constant Hamiltonians are time optimal for these constraints. We give an explicit formula for the time in these cases, in terms of the resource constraint. We show how our method produces a rich family of speed limit results, of which the generalized Margolus–Levitin theorem and the Mandelstam–Tamm inequality are special cases. We discuss the broader context of geometric approaches to speed limits in physical computation, including the way geometric approaches to quantum speed limits are a model for physical speed limits to computation arising from a limited resource.

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The impact of reducing the maximum speed limit on motorways in Switzerland to 80km h−1 on emissions and peak ozone

Environmental Modelling & Software ◽

10.1016/j.envsoft.2007.04.008 ◽

2008 ◽

Vol 23 (3) ◽

pp. 322-332 ◽

Cited By ~ 20

Author(s):

Johannes Keller ◽

Sebnem Andreani-Aksoyoglu ◽

Michel Tinguely ◽

Johannes Flemming ◽

Juerg Heldstab ◽

...

Keyword(s):

Maximum Speed ◽

Speed Limit ◽

The Impact

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Efektivitas Rambu Batas Kecepatan di Jalan Kolektor

Jurnal Teknik ◽

10.37031/jt.v18i2.98 ◽

2020 ◽

Vol 18 (2) ◽

pp. 73-81

Author(s):

Yulianggi Trisya Pramesti ◽

Anton Budiharjo

Keyword(s):

Traffic Accidents ◽

Short Term Memory ◽

Maximum Speed ◽

Speed Limit ◽

Short Term ◽

Storage Duration ◽

Speed Limits ◽

Term Memory ◽

Paired Sample ◽

Sample Test

One of the causes of traffic accidents is the non-compliance of motorized vehicle drivers to comply with the maximum speed limits that have been set. This study discusses and analyzes the effectiveness of the maximum speed limit signs that have been installed on Jalan Perintis Kemerdekaan, Cilacap Regency and provides recommendations for increasing the effectiveness of the maximum speed limit signs. The method used is a direct survey in the field and data analysis of the T-Paired Sample Test, as well as assessing the effectiveness using the N-Gain Score. From the analysis, it was found that the effectiveness of the existing signs was 6.25%. Short-Term Memory is related to what a person thinks when receiving a stimulus from the environment with a storage duration of 15-20 seconds. The storage duration can increase up to 20 minutes if there is repetition of information. To increase the effectiveness of speed limit signs, a simulation of the installation of speed limit signs is carried out repeatedly.

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NCHRP Report 350 Testing of W-Beam Slotted-Rail Terminal

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1599-03 ◽

1997 ◽

Vol 1599 (1) ◽

pp. 22-31 ◽

Cited By ~ 1

Author(s):

King K. Mak ◽

Hayes E. Ross ◽

Roger P. Bligh ◽

Wanda L. Menges

Keyword(s):

High Speed ◽

Safety Performance ◽

The Other ◽

Federal Aid ◽

Speed Limits ◽

Crash Testing ◽

National Highway ◽

Level 3 ◽

Test Level ◽

Highway System

Two slotted-rail terminal (SRT) designs, one for use on roadways with speed limits of 72.4 km/hr (45 mi/hr) or less and the other for high-speed facilities, were previously developed and successfully crash-tested in accordance with guidelines set forth in NCHRP Report 230. Those SRT designs have been approved by FHWA for use on federal-aid projects. However, FHWA has since adopted NCHRP Report 350 as the official guidelines for safety performance evaluation of roadside features and required that all roadside features to be used on the National Highway System be crash-tested in accordance with the NCHRP Report 350 guidelines by 1998. It is therefore necessary to modify and retest the SRT designs in accordance with NCHRP Report 350 guidelines. The modified SRT design has successfully met the guidelines set forth in NCHRP Report 350 for Test Level 3 conditions, that is, 100-km/hr (62.2 mi/hr) and the results of the crash testing. The modified SRT design has been approved by FHWA for use on the national highway system.

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Rule system for speed limit determination on national roads in Poland

MATEC Web of Conferences ◽

10.1051/matecconf/201823102001 ◽

2018 ◽

Vol 231 ◽

pp. 02001 ◽

Cited By ~ 1

Author(s):

Wojciech Chmiel ◽

Andrzej Dziech ◽

Stanisław Jędrusik ◽

Piotr Kadłuczka ◽

Joanna Kwiecień ◽

...

Keyword(s):

United States ◽

Data Model ◽

Legal Aspects ◽

Maximum Speed ◽

Speed Limit ◽

Speed Limits ◽

Rule Based ◽

Qualitative And Quantitative ◽

Rule Based System ◽

Rule System

Nowadays, in the majority of cases, speed limits are defined by experts, who take into account the qualitative and quantitative parameters of the examined roads. The process of setting speed limits is often complex, because technical, social, and legal aspects should be taken into account. The paper presents a developed rule-based system for setting maximum speed limits, and results of the research with an unified data model describing roads and their surroundings. Analysis of the possibility of obtaining relevant data and automation of the process of their collection are also described. The set of the rules was developed on the basis of the methodologies used in Poland, United States, Germany, and New Zealand.

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Exploring the Impact of Differentiated Per-Lane Speed Limits on Traffic Safety of Freeways with Considering the Compliance Rate

Journal of Advanced Transportation ◽

10.1155/2018/8368294 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 3

Author(s):

Meiyu Liu ◽

Jing Shi

Keyword(s):

Cellular Automata ◽

Traffic Safety ◽

Coefficient Of Variation ◽

Compliance Rate ◽

Speed Limit ◽

Speed Limits ◽

Lane Changing ◽

Incident Rate ◽

The Right ◽

The Impact

This is a subsequent study of a two-lane cellular automata (CA) traffic simulation model proposed by the authors. The current study focused on understanding the impacts of the configuration of the differentiated per-lane speed limit (DPLSL) and its compliance rate on traffic safety indexes, including lane-changing frequency, the coefficient of variation of speed, and incident rate of dangerous situations. The results indicate that freeway sections with DPLSL, especially the ones with complex DPLSL, have potentials to reduce the speed variation, lane changing frequencies, and chances of dangerous situations, resulting in higher traffic safety levels. Furthermore, under DPLSL configurations, the compliance rate of the lane of slow vehicles could positively affect the traffic safety levels. Specifically, as the decrease of the compliance rate, lane changing frequency slightly increases, the coefficient variation of speed especially of the outer lane increases, and the incident rate of the overtaking-on-the-right circumstances increases. In contrast to the simple DPLSL, freeway segments with the complex DPLSL configuration are more sensitive to the influence of the compliance rate.

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Analysis of Rural Interstate Fatality Rates in Consideration of Recent Increases in Maximum Statutory Speed Limits

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198119851758 ◽

2019 ◽

Vol 2673 (11) ◽

pp. 48-58

Author(s):

Jacob Warner ◽

Hitesh Chawla ◽

Chao Zhou ◽

Peter T. Savolainen

Keyword(s):

Traffic Safety ◽

Negative Binomial ◽

Unobserved Heterogeneity ◽

State Level ◽

Random Parameter ◽

Maximum Speed ◽

Speed Limit ◽

Speed Limits ◽

Fatal Crashes ◽

Significant Research

The relationship between traffic safety and speed limits has been an area of significant research. Since the repeal of the National Maximum Speed Law in 1995, states have full autonomy in establishing maximum statutory speed limits. Since 2001, at least 25 states have increased their maximum limits to speeds as high as 85 mph. This study examines changes in rural interstate fatalities from 2001 to 2016 in consideration of such increases. Speed limit policy data include the maximum speed limit for each state–year combination, as well as the proportion of rural interstate mileage posted at each speed limit in each state. Random parameter negative binomial models are estimated to control for unobserved heterogeneity, as well as time-invariant effects unique to each state. The results show that increasing the mileage of rural interstates posted at 70, 75, or 80 mph by 1% is associated with fatality increases of 0.2%, 0.5%, and 0.6%, respectively. These increases are more pronounced than when considering only the maximum statutory limits in each state. The study also examines the influence between these higher limits and the frequency of fatal crashes involving speeding and driver distraction. At the highest limits of 75 and 80 mph, the increases among these subsets of crashes are greater than the increases in total fatalities. Ultimately, this study provides important empirical evidence in support of continuing speed limit policy discussions, in addition to identifying salient analytical concerns that should be considered as a part of longitudinal analyses of state-level fatality data.

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Estimation of Optimal Speed Limits for Urban Roads Using Traffic Information Big Data

Applied Sciences ◽

10.3390/app11125710 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5710

Author(s):

Hyungkyu Kim ◽

Doyoung Jung

Keyword(s):

Traffic Safety ◽

Safety Information ◽

Traffic Information ◽

Maximum Speed ◽

Speed Limit ◽

Speed Limits ◽

The Road ◽

Optimal Speed ◽

Road Users ◽

Adjustment Factors

The use of an inconsistent speed limit determination method can cause low speed limit compliance. Therefore, we developed an objective methodology based on engineering judgment considering the traffic accident rate in road sections, the degree of roadside development, and the geometric characteristics of road sections in urban roads. The scope of this study is one-way roads with two or more lanes in cities, and appropriate sections were selected among all roads in Seoul. These roads have speed limits of the statutory maximum speed of 80 km/h or lower and are characterized by various speeds according to the function of the road, the roadside development, and traffic conditions. The optimal speed limits of urban roads were estimated by applying the characteristics of variables as adjustment factors based on the statutory maximum speed limit. As a result of investigating and testing various influence variables, the function of roads, the existence of median, the level of curbside parking, the number of roadside access points, and the number of traffic breaks were selected as optional variables that influence the operating speed. The speed limit of one-way roads with two or more lanes in Seoul was approximately 10 km/h lower than the current speed limit. The existing speed limits of the roads were applied uniformly considering only the functional road class. However, considering the road environment, the speed limit should be applied differently for each road. In the future, if the collection scope and real-time collection of road environment information can be determined, the GIS visualization of traffic safety information will be possible for all road sections and the safety of road users can be ensured.

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