Xiaofei Ye

Features of bicycle abreast riding and its application in bicycle facility operating evaluation and design optimization

This article aims to measure bicycle facility operating state based on the survey and analysis of bicycles’ abreast riding. We conducted a detailed bicycle operating investigation consisting of four exclusive bicycle paths in Nanjing, China, and introduced an approach to extract the data of bicycle abreast riding from bicycle arrival data. Then, the relationships between bicycle volume and bicycle group size, abreast riding number, lateral clearance, and path width occupancy were discussed. In the end, we compared passing event, macro bicycle flow parameter, and single riding ratio in representing a cyclist’s individual comfort, suitability, and difficulty to data acquisition. The results and conclusions we obtained are as follows: (1) bicycle group size, abreast riding, and path width availability keep a positive correlation with bicycle volume, respectively, while single riding proportion and lateral clearance have a negative relationship with it. (2) Bicycle single riding proportion is a better parameter reflecting bicycle level of service from an objective perspective. We first studied bicycle abreast riding from a vantage point of bicycle group. Single riding proportion offers bicycle facility appraisers another possible choice to assess bicycle level of service. Path width occupancy is very useful in optimizing bicycle facility.

Modified Road Speed Models Considering Traffic Flow with and without Bus Lanes and Analysis of the Condition of Setting Bus Lanes

In order to analyze the traffic flow performance of a road with and without the implementation of a bus-lane more accurately, this paper introduces a basic road speed model and its applicability. Then we modified the model’s formulation of car and bus by considering different traffic parameters such as car volume, bus volume, and bus-to-car ratio. We also put forth the methods used for coefficient calibration. We collected the empirical data from two three-lane, one-way road sections with and without a bus lane to calibrate the modified road speed models respectively. Comparing the different speeds between the traffic flow with and without bus lane implementation, we obtained the result that the speed varied for two distinct intervals: one with no difference and one with increased difference as the road traffic volume (saturation) changed. Furthermore, the time utility models were set up to describe the traffic volume condition of setting a bus lane. The conclusion shows that the traffic volume is lower than the traditional standard when the proportion of buses is low and vice versa. Therefore, identifying the proportion of traffic within the composition of public transportation would help refine the analysis of setting a bus lane.

Impact of Curbside Parking on Bicycle Lane Capacity in Nanjing, China:

As roadway resources are being occupied by curbside parking and because of the operational characteristics of parking maneuvers, the capacity of the adjacent travel lane can be significantly reduced. To analyze the influence of curbside parking on the capacity of the bicycle lane, a conflict technique based on additive conflict flow was applied to establish the base capacity model. The actual capacity of the bicycle lane with curb parking was then established by adjusting the base capacity to reflect the influence: lane width, the time influence of parking maneuvers, and proportion of e-bikes. Eight datasets from the exclusive bicycle lanes with different widths and parking maneuvers were collected in Nanjing, China for calibration and evaluation purposes. As a result of a higher number of parking maneuvers, the Emeiling Road was taken as the main case study. The capacity of the bicycle lane was calculated, and the effectiveness of the proposed method was validated by the speed-density-volume relationship model. The proposed model was applied to analyze the effect of different positions of parking berths on the capacity. The results indicate that, with around 65% share of e-bikes, the estimated capacity of Emeiling Road is 2622 bicycles/h, decreasing by 47.10% under the influence of curbside parking. The results also imply that the berths near the openings of the isolation belt have less influence than those in the middle position. These findings could be helpful and useful for practitioners to improve the capacity of bicycle lanes under the influence of curbside parking.

Understand e-bicyclist safety in China: Crash severity modeling using a generalized ordered logit model

A thorough crash modeling effort was made to examine e-bicyclists’ injury severity, using a generalized ordered logit model, which can capture the ordinal nature of injury severity and allow for heterogeneity across observations. A number of factors associated with injury severity of e-bicyclists are identified, including older e-bicyclists, heavy truck involved, e-bicyclist at fault, e-bicyclist turn left, e-bicyclist cross the road, driver turn right, industrial area, weekday, and tree separation. Safety countermeasures and interventions are thus proposed based on the modeling results, including developing educational programs for specific age groups (e.g. older e-bicyclists, female e-bicyclists, and inexperienced drivers), launching safety campaigns, improving geometric design and traffic control in low-developed area, curve roads, and signalized intersections. Moreover, some interesting research topics are also suggested, such as examining head-on e-bike crash mechanism, crash mechanism between e-bicyclists and heavy trucks and motorcycles, and safety effects of different separation treatments on e-bicyclists’ injury severity from kinetic and kinematic perspectives.

Effect of Parking Charges on Shared Parking Behavior Based on Trip Purposes

With the rapid development of private cars, limited parking facilities can’t meet the increasing parking demand. To solve the problem, shared parking is proposed to balance the parking demand and supply. On this basis, parking charge, as an effective method to guide shared parking, becomes an important issue. In this paper, a stated preference (SP) survey regarding shared parking and parking charge was conducted. Then, according to different trip purposes, two binary logit models were established to analyze the influence of varied parking charges on shared parking behavior. Finally, elasticity about parking price was analyzed in this paper. It was showed that both commuters and non-commuters are most sensitive to the price discrepancy of 3-4 yuan. Also, the paper showed a gap in price sensitivity between commuting trips and non-commuting trips.

Traffic Delay of Vehicles Based on Traffic Flow Wave Theory Caused by Curb-Lane Bus Stop

To enhance the utilization efficiency and accessibility of curb-lane bus stops and minimize the impacts on dynamic traffic flow, traffic delay models based on traffic flow wave theory was proposed after investigating and analyzing four curb-bus stops in Nanjing. Those models were used to describe traffic delay in the condition of no-signalized intersections flow, dissipated flow in green times, dissipated flow in a signal cycle, and interactive flow in next signal cycle. Practical examples of vehicle arrivals show that the vehicle arriving characteristic is continuous and interacted on urban roadway affected by signalized intersections flow. A compressional dilatational wave was found near curb-lane bus stops, which has three states of consciousness, expandability, and dissipation. The proposed approach can be applied to describe the delay of traffic delay effectively.

LEVEL OF SERVICE OF CURBSIDE PARKING FACILITIES BASED ON PARKING ACCESSIBILITY

The paper presents a study to establish a method of measuring parking efficiency and accessibility of curbside parking facilities based on the level-of-service (LOS) concept. This paper selected curb parking facilities setting on the bicycle lane, analyzed accessibility of inbound and outbound parking maneuvers influenced by non-motorized vehicle flow, and then identified and evaluated a group of principal variables that influence parking accessibility. Based on traffic conflict analysis techniques and traffic survey, the authors defined the events of conflicts to describe the traffic block and traffic conflict of parked vehicles caused by non-motorized vehicle flow and then established a model to describe the relationship between the events of conflicts and the velocity of non-motorized vehicles and parked car, bicycle, and e-bike volume, the width of bicycle lane. The results indicated that the events of parking conflicts increased significantly with increasing the non-motor vehicle volumes and decreasing velocity difference between parked car and non-motor vehicles. Finally, the relationship model was included in the derived method for designating the level of service of curbside parking facilities; it is hoped that the LOS criteria would help to provide theoretical support for setting and building of curb parking facilities.

KALMAN FILTERING ESTIMATION OF ARRIVAL RATE FOR OFF-STREET PARKING LOTS

Estimating accurately the arrival rate of the off-street parking lot is very important for studying the impact the park imposes to the main road. The data in this paper are derived from raw counts by the video. Then the Kalman filtering estimation is applied for estimating the arrival numbers of different time steps. Using the Matlab, Kalman filtering estimation gets good results. The results obtained demonstrate that the Kalman filtering is fit for the arrival rate prediction. Through comparing the results of different time steps, two conclusions can be got: the more time steps are taken into the model, the result will be better; the results of longer time step are better than the shorter.