Calibration and accuracy assessment of Leica ScanStation C10 terrestrial laser scanner

Requirement of high accuracy data in surveying applications has made calibration procedure a standard routine for all surveying instruments. This is due to the assumption that all observed data are impaired with errors. Thus, this routine is also applicable to terrestrial laser scanner (TLS) to make it available for surveying purposes. There are two calibration approaches: (1) component, and (2) system calibration. With the intention to specifically identify the errors and accuracy of the Leica ScanStation C10 scanner, this study investigates component calibration. Three components of calibration were performed to identify the constant, scale error, accuracy of angular measurement and the effect of angular resolution for distance measurement. The first calibration has been processed using closed least square solutions and has yielded the values of constant (1.2 mm) and scale error (1.000008879). Using variance ratio test (F-Test), angles observation (horizontal and vertical) for Leica C10 scanner and Leica TM5100A theodolite have shown significance difference. This is because the accuracy of both sensors are not similar and these differences are 0.01 and 0.0075º for horizontal and vertical measurements, respectively. Investigation on the resolution setting for Leica C10 scanner has highlighted the drawback of the tilt-and-turn target. Using the highest resolution, Leica Cyclone software only able to recognize the tilt-and-turn target up to 10 m distance compare to 200 m for the black and white target

Achieving genuinely dynamic road user charging : issues with a GNSS-based approach

Peer reviewedPostprin

Integrated Accident Resilience Framework (IARF) – A Theoretical Approach Using Spatial and Statistical Analysis

Throughout the world, road accidents have become a nightmare for any local government. Data shows that every 24 seconds someone dies on the road (WHO, 2018). Generally, there are multiple factors causing road accidents such as traffic volumes/composition, speed, infrastructure conditions, climatic conditions, and vehicle factors etc. Through this paper, an effort has been made to bring an effective Integrated Accident Resilience Framework (IARF). The framework is in the form of a theoretical method which may help transportation agencies and governments to develop a practical system for crash analysis and mitigation. The Integrated Accident Resilience Framework (IARF) showcased in this paper consists of different stages such as data collection, storage, and analysis, which help to compute correlations between crash causational parameters and crash frequency. The tools used to perform the analysis functions in the framework consist of the GIS platform, as well as the application of the negative binomial regression model. The computed results help identify the major influencing parameters that are linked to traffic accidents and their contribution to crash frequency in black spot locations. This can be used to mitigate future crashes by taking appropriate remedial measures in collision-prone regions. The methodology presented can also be scaled up to a city level network. The entire transportation network can be spatially marked to develop a resilient accident management strategy; even a real-time also

Identification of Hazardous Road Locations for Pedestrians

AbstractHot zone methodology is promising in the identification of hazardous road locations. The key steps involve geo-validation of road crashes, segmentation of road network into basic spatial units (BSUs), calculation of actual crash intensity, definition of threshold value, and examination of spatial proximity of BSUs. This research applies the hot zone methodology to identify dangerous road locations for pedestrians during the study period of 2005 to 2007 in Kwun Tong District of Hong Kong. In particular, the crash intensity was calculated by a casualty-weighted method, which assigns different weights to different injury severity types. Two negative binomial regression models were employed to determine the threshold values. One could be treated as a base model which includes the length of BSU as the only explanatory variable. The other, regarded as a full model, introduces diverse environmental variables that might have influenced the distribution of pedestrian casualties

Sharing of gis spatial data intransportation engineering

Geographic Information System (GIS) is classified as an information technology to solve various spatial problems in civil engineering. GIS provides spatial information to the system and therefore, complex spatial analysis of problem could be carried out. The objective of this paper is to promote the use of GIS as a tool for civil engineering problem solving. This paper describes the work undertaken to demonstrate the potential use of GIS in civil engineering via a prototype project. The presentation of this article is mainly focused on the applications of GIS in transportation engineering including transportation, highway and traffic. Moreover, this study could also contribute relevant and benefit guidance to the public and private sectors with techniques in determining potential activity using the GIS software. The utilisation of GIS can prepare and contributes towards a profitable cost and effective service. The end product should be an effective information system and a final potential GIS map. With GIS support, it could assist user to make a more effective and efficient decision on any difficulties that will arise. Compared to the conventional methods, the system provides a proper and an effective, update and accessible result of spatial analysis

Safety in numbers for cyclists beyond national-level and city-level data: a study on the non-linearity of risk within the city of Hong Kong

published_or_final_versio

Pedestrian route choice: an empirical study

There has been relatively little work done on route choice for pedestrians. The present paper addresses this issue by using a sample survey of daily walks in a UK urban area. The walks undertaken are reconstructed using a geographical information system and compared with the shortest available route. It was found that about 75 per cent of walkers in the sample chose the shortest available route. Two strategies were used to synthesise sets from which pedestrians could have chosen their routes. These choice sets can then be used in discrete choice modelling to study route choice and to determine which factors are important to pedestrians in this. At the time of writing, it is proposed to proceed with this modelling. The structure of the paper is as follows. Section 2 describes the various sources of data used in this work, section 3 discusses the choice set generation strategies that were developed, section 4 briefly compares the walks with the corresponding shortest routes, while section 5 presents the conclusions that were drawn from this

Predicting crash frequency using an optimised radial basis function neural network model

With the enormous losses to society that result from highway crashes, gaining a better understanding of the risk factors that affect traffic crash occurrence has long been a prominent focus of safety research. In this study, we develop an optimised radial basis function neural network (RBFNN) model to approximate the nonlinear relationships between crash frequency and the relevant risk factors. Our case study compares the performance of the RBFNN model with that of the traditional negative binomial (NB) and back-propagation neural network (BPNN) models for crash frequency prediction on road segments in Hong Kong. The results indicate that the RBFNN has better fitting and prediction performance than the NB and BPNN models. After the RBFNN is optimised, its approximation performance improves, although several factors are found to hardly influence the frequency of crash occurrence for the crash data that we use. Furthermore, we conduct a sensitivity analysis to determine the effects of the remaining input variables of the optimised RBFNN on the outcome. The results reveal that there are nonlinear relationships between most of the risk factors and crash frequency, and they provide a deeper insight into the risk factors’ effects than the NB model, supporting the use of the modified RBFNN models for road safety analysis.postprin

Evaluating the effects of road hump on speed and noise level at a university setting

This study is carried out to determine the effectivness of road humps to reduce the traffic speed and traffic noise in institutional area. The difference in hump profiles in terms of height, width and length are the main factors in determing the effectiveness of road humps. The difference in the profiles of the road hump will cause changing driver behaviour of the users especially when approaching the road hump. The road humps with different design profiles are selected to measure the speed and noise level of the vehicles at, before and after each of the selected road humps. Radar speed gun and noise level meters are used to measure speed and noise level of the vehicles at each of designated points along the major circular road in IIUM. The changes in speed and noise level at different selected points at each of the different profiles of the road humps are the expected findings of this study

Evaluating the effects of road hump on the speed of vehicles in an institutional environment

Vehicles travelling at speed above the permissible speed limit have jeopardized the safety of road users. The concern is greater at institutional environment whereby most road users travel by walking. Road hump is considered as an efficient traffic calming measure in reducing the speed of the vehicle. This paper investigates the effects of different road hump dimensions in decreasing the speed of vehicles at the main road of International Islamic University Malaysia. Six (6) road humps with different design profile were selected. The design profile and spot speed of the vehicles at all six (6) road humps were measured. The speed of vehicles at the road hump was analyzed by using descriptive analysis and t-test. The findings of this study suggest that road hump is effective in lowering the speed of vehicles in an institutional environment. The dimensions of road hump, especially height, influence significantly the speed reduction of vehicles