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Apeldoorn, Netherlands

Schepers J.P.,Center for Transport and Navigation | Heinen E.,University of Groningen
Accident Analysis and Prevention | Year: 2013

Governments aim to promote a shift from car to bicycle, but concerns about road safety seem to represent an important argument against this encouragement. This study examines the road safety impact of a modal shift from short car trips to cycling in Dutch municipalities. The road safety effect is estimated using Accident Prediction Models (APMs) that account for the non-linearity of risk. APMs are developed utilizing Negative Binomial regression. This study is the first to develop APMs using crash and mobility data from municipalities, and utilizing these models to estimate the effects of changing modal splits of current car and bicycle use to modal splits that actually exist in these municipalities. The results suggest that, under conditions such as in Dutch municipalities, transferring short trips made by cars to bicycles does not change the number of fatalities, but increases the number of serious road injuries. The neutral effect on fatalities, despite the high fatality risk for cyclists, can be explained by there being fewer cars on the road to pose a risk to others, the shorter length of bicycle trips compared to the car trips they replace, and the "safety in numbers" phenomenon. The rise in the number of serious road injuries is due wholly to the high number of cycling crashes with no other vehicle involved. The effect of a modal shift is dependent on the age of the population in which the shift is concentrated, and can be influenced by measures affecting cyclists' injury risk. © 2012 Elsevier Ltd. Source


Hamzah M.O.,Universiti Sains Malaysia | Hasan M.R.M.,Universiti Sains Malaysia | Van de Ven M.F.C.,Technical University of Delft | Voskuilen J.L.M.,Center for Transport and Navigation
RILEM Bookseries | Year: 2012

Stripping is a major source of pavement distress and takes place in the presence of moisture. Over the years, many laboratory tests have been proposed to evaluate moisture sensitivity of asphalt mixtures. This paper presents the development of a dynamic asphalt stripping machine (DASM) to realistically simulate stripping of porous asphalt mixtures subjected to the dynamic action of flowing water. To assess the effectiveness of the machine, two sets of specimens were prepared. One set was conditioned in the DASM by allowing water at 40oC to continuously permeate through the unextruded samples via water sprinklers at an intensity equivalent to 5400 mm/hr. The other set was stored under dry conditions at ambient temperature. Then, both sets of specimens were extruded and conditioned in an incubator before individually tested for Indirect Tensile Strength (ITS) at 20oC after 1, 3, 5 and 7 days. Resistance to stripping was evaluated from the ratio between ITS when tested wet and dry. Specimen permeability was also measure before and after conditioning. In addition, mortars that stripped from the asphalt samples were filtered on a filter material. The results showed that both ITSR and permeability reduces with conditioning time. The ITSR after 7-day conditioning was 17.2% lower than those conditioned for one day. The quantity of mortars collected on the filter material was found to increase with conditioning time. However, some stripped mortars were believed to be trapped in the mixture capillaries, and this explained the reduction in coefficient of permeability values over time. © RILEM 2012. Source


Hofman R.,Center for Transport and Navigation
40th International Congress and Exposition on Noise Control Engineering 2011, INTER-NOISE 2011 | Year: 2011

Rijkswaterstaat, the Dutch State Road Authority, has the policy to use silent pavement on its entire road network. The main reason for focus on silent pavements is that they are relative cheap compared to other measures, like noise barriers, tunnels and sunk roads. Additionally, procedure time for construction allowance is high for traditional measures. For a new material such as Poro Elastic Road Surfaces (PERS) the advantage of cost effectiveness is not evident and has to be determined. Rijkswaterstaat made a simple calculation to exploit the life cycle costs of PERS. It turns out that the intrinsic materials costs of PERS is quite high, approximately 5 to 10 times more expensive than traditional asphalt. Therefore, product development has to focus on; cheap elastic materials, reasonable constructive strength/lifetimes under motorway conditions and high noise reductions of at least 10 dB (Dutch scale). Furthermore, the necessary budget increases rapidly when more lanes should have PERS; other alternatives, such as high noise barriers, might in the case of roads with multiple lanes even be more cost effective. Copyright © (2011) by the Institute of Noise Control Engineering. Source


De Gruijter D.,Ministry of Housing | Hageman E.,Center for Transport and Navigation
39th International Congress on Noise Control Engineering 2010, INTER-NOISE 2010 | Year: 2010

In the Netherlands it is commonly accepted that the cost of a noise barrier is much too high to solve a noise problem for just one house, but what about ten houses or a hundred? Therefore a cost-benefit analysis is part of the design process of noise measures. The cost of noise barriers, silent pavements etc. are weighted against the acoustic benefits. Up to now several methods were in use, each with different goals and merits, but also drawbacks. Now there is one new easy method for all purposes. The method is part of the new noise legislation for highways and railways. Source


Hof B.,SEO Economic Research | Heyma A.,SEO Economic Research | van der Hoorn T.,Center for Transport and Navigation
Transportation | Year: 2012

A case is set up concerning a fictitious Dutch high-speed railway project involving passenger transport. Direct welfare effects are calculated using a standard transport model. On the basis of the case description and the direct effects, five models calculate total welfare effects and wider (indirect) economic benefits. The results of these models are compared. In very broad terms, differences in results can be explained, but on a more detailed level, differences remain that are hard to explain. We also find that large differences in results are caused by differences in the way direct welfare effects are calculated, instead of by differences in wider economic benefits. This suggests that it pays a lot more to focus on understanding and improving direct effect calculations than to try and perfectly quantify wider economic benefits. © 2011 The Author(s). Source

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