scholarly journals The Cost of Hauling Timber: A Comparison of Raster- and Vector- Based Travel-Time Estimates in GIS

2000 ◽  
Author(s):  
Sara Loreno
Keyword(s):  
Travel Time ◽  
Time Estimates ◽  
The Cost

scholarly journals “In cities, it’s not far, but it takes long”: comparing estimated and replicated travel times to reach life-saving obstetric care in Lagos, Nigeria

2021 ◽  
Vol 6 (1) ◽  
pp. e004318
Author(s):  
Aduragbemi Banke-Thomas ◽  
Kerry L M Wong ◽  
Francis Ifeanyi Ayomoh ◽  
Rokibat Olabisi Giwa-Ayedun ◽  
Lenka Benova
Keyword(s):  
Travel Time ◽  
Friction Surface ◽  
Obstetric Care ◽  
Travel Times ◽  
Night Time ◽  
Google Maps ◽  
Surface Approach ◽  
Low Resource ◽  
Life Saving ◽  
The Cost

BackgroundTravel time to comprehensive emergency obstetric care (CEmOC) facilities in low-resource settings is commonly estimated using modelling approaches. Our objective was to derive and compare estimates of travel time to reach CEmOC in an African megacity using models and web-based platforms against actual replication of travel.MethodsWe extracted data from patient files of all 732 pregnant women who presented in emergency in the four publicly owned tertiary CEmOC facilities in Lagos, Nigeria, between August 2018 and August 2019. For a systematically selected subsample of 385, we estimated travel time from their homes to the facility using the cost-friction surface approach, Open Source Routing Machine (OSRM) and Google Maps, and compared them to travel time by two independent drivers replicating women’s journeys. We estimated the percentage of women who reached the facilities within 60 and 120 min.ResultsThe median travel time for 385 women from the cost-friction surface approach, OSRM and Google Maps was 5, 11 and 40 min, respectively. The median actual drive time was 50–52 min. The mean errors were >45 min for the cost-friction surface approach and OSRM, and 14 min for Google Maps. The smallest differences between replicated and estimated travel times were seen for night-time journeys at weekends; largest errors were found for night-time journeys at weekdays and journeys above 120 min. Modelled estimates indicated that all participants were within 60 min of the destination CEmOC facility, yet journey replication showed that only 57% were, and 92% were within 120 min.ConclusionsExisting modelling methods underestimate actual travel time in low-resource megacities. Significant gaps in geographical access to life-saving health services like CEmOC must be urgently addressed, including in urban areas. Leveraging tools that generate ‘closer-to-reality’ estimates will be vital for service planning if universal health coverage targets are to be realised by 2030.

scholarly journals The Effect of Route-choice Strategy on Transit Travel Time Estimates

2019 ◽  
Author(s):  
Nate Wessel ◽  
Steven Farber
Keyword(s):  
Travel Time ◽  
Shortest Path ◽  
Imperfect Information ◽  
Optimal Path ◽  
Shortest Paths ◽  
Route Choice ◽  
Travel Times ◽  
Selection Strategies ◽  
Time Estimates ◽  
Average Travel Time

Estimates of travel time by public transit often rely on the calculation of a shortest-path between two points for a given departure time. Such shortest-paths are time-dependent and not always stable from one moment to the next. Given that actual transit passengers necessarily have imperfect information about the system, their route selection strategies are heuristic and cannot be expected to achieve optimal travel times for all possible departures. Thus an algorithm that returns optimal travel times at all moments will tend to underestimate real travel times all else being equal. While several researchers have noted this issue none have yet measured the extent of the problem. This study observes and measures this effect by contrasting two alternative heuristic routing strategies to a standard shortest-path calculation. The Toronto Transit Commission is used as a case study and we model actual transit operations for the agency over the course of a normal week with archived AVL data transformed into a retrospective GTFS dataset. Travel times are estimated using two alternative route-choice assumptions: 1) habitual selection of the itinerary with the best average travel time and 2) dynamic choice of the next-departing route in a predefined choice set. It is shown that most trips present passengers with a complex choice among competing itineraries and that the choice of itinerary at any given moment of departure may entail substantial travel time risk relative to the optimal outcome. In the context of accessibility modelling, where travel times are typically considered as a distribution, the optimal path method is observed in aggregate to underestimate travel time by about 3-4 minutes at the median and 6-7 minutes at the \nth{90} percentile for a typical trip.

scholarly journals A Study on Contestable Regions in Europe through the Use of a New Rail Cost Function: An Application to the Hinterland of the New Container Terminal of Leghorn Port

2019 ◽  
Vol 2019 ◽  
pp. 1-35 ◽  
Author(s):  
Marino Lupi ◽  
Antonio Pratelli ◽  
Mattia Canessa ◽  
Andrea Lorenzini ◽  
Alessandro Farina
Keyword(s):  
Cost Function ◽  
Travel Time ◽  
Container Terminal ◽  
Maximum Speed ◽  
Rail Network ◽  
Insurance Costs ◽  
Rail Line ◽  
Staff Cost ◽  
The Cost ◽  
Cost Components

In this paper, the potential hinterland of the new container terminal of the port of Leghorn (Livorno in Italian) is studied. The study actually analyses the competitiveness of major European ports with respect to some of the most contestable regions in Europe. Travel time and monetary costs of railway paths, connecting ports to their hinterland, have been determined. The rail network of a large part of Europe was modelled using a graph. To each link, which represents a portion of the rail line, a cost function is associated. The travel time on the link is determined from the average speed, which has been determined from the maximum speed via formulae obtained through linear regression. The few cost functions that exist in current literature for the computation of the cost of a rail link are not detailed enough. Therefore, a new cost function has been developed. All cost components were determined in detail: the staff cost, the amortisation, maintenance, and insurance costs of locomotives and wagons, the cost of the usage of rail track, the traction cost. The traction cost was calculated in detail from all resistances to motion. Moreover, for each rail link, the number of locomotives needed to operate the train and the maximum towable weight were determined. The monetary value of time in freight transport registers a high variability; therefore, three different optimisations of the paths—by travel times, monetary costs, and generalised costs—between each origin–destination pair were carried out. The rates of competitiveness of the ports with respect to the examined European contestable regions were analysed.

scholarly journals A Novel On-Ramp Merging Strategy for Connected and Automated Vehicles Based on Game Theory

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Haigen Min ◽  
Yukun Fang ◽  
Runmin Wang ◽  
Xiaochi Li ◽  
Zhigang Xu ◽  
...  
Keyword(s):  
Game Theory ◽  
Travel Time ◽  
Fuel Consumption ◽  
Transportation Network ◽  
Control Algorithms ◽  
Traffic Density ◽  
Automated Vehicles ◽  
Network Efficiency ◽  
Total Travel Time ◽  
The Cost

Connected and automated vehicles (CAVs) have attracted much attention of researchers because of its potential to improve both transportation network efficiency and safety through control algorithms and reduce fuel consumption. However, vehicle merging at intersection is one of the main factors that lead to congestion and extra fuel consumption. In this paper, we focused on the scenario of on-ramp merging of CAVs, proposed a centralized approach based on game theory to control the process of on-ramp merging for all agents without any collisions, and optimized the overall fuel consumption and total travel time. For the framework of the game, benefit, loss, and rules are three basic components, and in our model, benefit is the priority of passing the merging point, represented via the merging sequence (MS), loss is the cost of fuel consumption and the total travel time, and the game rules are designed in accordance with traffic density, fairness, and wholeness. Each rule has a different degree of importance, and to get the optimal weight of each rule, we formulate the problem as a double-objective optimization problem and obtain the results by searching the feasible Pareto solutions. As to the assignment of merging sequence, we evaluate each competitor from three aspects by giving scores and multiplying the corresponding weight and the agent with the higher score gets comparatively smaller MS, i.e., the priority of passing the intersection. The simulations and comparisons are conducted to demonstrate the effectiveness of the proposed method. Moreover, the proposed method improved the fuel economy and saved the travel time.

scholarly journals Cost of pruning Douglas-fir in coastal British Columbia

1994 ◽  
Vol 70 (1) ◽  
pp. 80-83
Author(s):  
S. A. Y. Omule ◽  
D. E. Paul ◽  
L. M. Darling
Keyword(s):  
British Columbia ◽  
Key Words ◽  
Travel Time ◽  
Douglas Fir ◽  
Time Study ◽  
Average Spacing ◽  
The Cost ◽  
Coastal British Columbia

Artificial pruning can increase the quantity of high-value clear lumber harvested from Douglas-fir, but the pruning cost per tree is relatively high. To prune a young Douglas-fir to 6 metres in one lift and two lifts took, respectively, 9.5 and 10.1 minutes in 14- and 18-year old stands with average spacing between trees of about 3 metres on flat or 0-30% south-facing slopes in coastal British Columbia. The associated costs were $2.09 and $2.22. This included minor travel time between trees, but excluded the cost of travelling to the site, selecting and marking trees to be pruned, and purchasing and maintaining the pruning equipment. Differences in pruning time between one-lift pruning and two-lift pruning, in one or two passes, were small. A D-handled saw was preferred to the more strenuous snap-cut pruner with ratchet-style pinions, based on observations on a pruning time-study of 5 operators. Key words: pruning saw, snap-cut pruner, pruning time, one-lift pruning, two-lift pruning

Estimation of Origin-Destination Matrix with Tolling Data

2011 ◽  
Vol 50-51 ◽  
pp. 239-244 ◽  
Author(s):  
Hua Wang ◽  
Xiao Ning Zhang
Keyword(s):  
Simulated Annealing ◽  
Travel Time ◽  
Road Network ◽  
Programming Model ◽  
Heuristic Method ◽  
Traffic Information ◽  
Traditional Model ◽  
Matrix Estimation ◽  
Od Estimation ◽  
The Cost

Prior matrix and surveyed link volumes were, in most cases, employed to estimate origin-destination matrix. With the development of BOT and of congestion pricing, charged links become an important component of road network, due to the fact that the tolling data: volumes and travel time on pricing entry-exit are traffic information, both cost-free and accurate. In this paper, we put forward a bi-level programming model, taking account of data on charging entry-exit to estimate OD matrix based upon the traditional model. Meanwhile, a heuristic method -the simulated annealing approach - is utilized to solve the OD estimation problem. Results of examples indicate that the accuracy of estimation will be improved while adding the tolling data, and that it is feasible to calculate OD matrix by combining the volumes and travel time on entry-exit with partial common link flows. In this light, this way can be applied to enhance accuracy, and also to reduce the cost spent on surveying the link flows in common OD matrix estimation.

Sign in / Sign up

Export Citation Format

Share Document