With the continuous improvement of the level of urban motorization, the traffic demand also increases, and urban traffic congestion and other problems also follow. If the traffic problem is not solved well, it will seriously hinder the social and economic development of the city. No matter from the international advanced experience, or from the occupation of roads and parking land, as well as energy conservation and environmental protection, the important way to solve urban traffic problems is to develop public transportation. This paper mainly puts forward specific measures to improve public transportation, so as to increase the sharing rate of urban public transportation and alleviate urban traffic congestion.
Keywords: public transportation; Travel; measure
foreword
Compared with other modes of transportation, buses occupy the most economical roads and parking land. The use efficiency of roads is measured by the number of people passing per cubic meter per hour, and buses are 10 to 15 times that of cars. The carrying capacity of a bus is equivalent to 16 taxis; Under dynamic conditions, 10 bicycles or 4 cars occupy the same road area as a bus with 150 passengers. From the point of view of energy saving and environmental protection, compared with private cars, public transportation saves 3/4 of land resources, 4/5 of building materials and 5/6 of investment. The road occupation length is reduced by nearly 90%, the fuel consumption is saved by about 20%, and the air pollution produced by private cars is 10 times that of buses; The incidence of traffic accidents is 100 times higher than that of buses. Developing public transport is an important way to solve urban traffic problems. Therefore, it is of practical significance and necessity to study how to improve the urban public transport trip to the urban traffic congestion problem.

1. Causes of difficulties in developing urban public transport
1.1 Public transport policy lags behind
Public transport planning can’t keep up with the development of the city, and the planning content is not perfect; The construction of urban public transport facilities is seriously inadequate; The development of urban public transport lacks a systematic and perfect legal guarantee and policy support system. The legal system of urban public transport industry in China is still far from perfect, which leads to the lack of necessary legal support, unclear subject, unclear rights and responsibilities, unplanned behavior and inadequate supervision. In terms of policy support, the investment in public transport infrastructure is generally insufficient, and the implementation of public transport priority strategy is not in place. Lack of scientific overall transportation strategy and long-term development planning, many departments and city decision-makers do not give long-term consideration to the current serious traffic situation, but only treat the symptoms from scratch, have inconsistent understanding and policies, and even continue to follow the road that other countries have proved to have failed. According to the development experience of cities in developed countries, the investment in urban public transport infrastructure should generally be kept at about 3%-5% of GDP, otherwise the function of public transport infrastructure will be difficult to guarantee. However, in 2001, the national investment in urban public transport was only 19 billion yuan, less than 1% of the national urban GDP. Due to the limitation of urban financial expenditure and the weakening of public transportation, the subsidies for public transportation in most cities are shrinking day by day. Although some cities maintain or increase their financial subsidies for public transportation, their service scope and service level actually decline due to the expansion of public transportation departments. In addition, in the process of marketization, a set of scientific and reasonable financial subsidy compensation mechanism has not been formed for public transport enterprises.Only pay attention to economic benefits, the public welfare of public transportation is difficult to reflect.
1.2 less public transport vehicles, low speed.
The number of urban public transport vehicles in China is relatively small, and the ownership rate of public transport vehicles is low. Due to the serious overload operation of public transport vehicles and the poor technical condition of vehicles, the running speed of vehicles is low and the service quality is difficult to satisfy passengers. There is a serious shortage of urban public transport capacity, and the bus transport capacity is tight and crowded during peak hours.
1.3 public transport travel time is too long
One of the main reasons for people’s dissatisfaction with public transportation is the long time of walking and waiting. Therefore, reducing the travel time of public transportation is the primary prerequisite for improving the attractiveness of public transportation.
1.4 the bus line coverage is low, and it is difficult to transfer.
In China’s urban development planning, there is a lack of overall planning strategy in public transport network planning and line layout, which makes the setting of public transport stations, bus line coverage and public transport transfer hub unable to meet the needs of passengers, and fails to consider the long-term development of the city. The layout is messy, the transfer is inconvenient, and many aspects are not connected and coordinated, and the transfer distance is long, which increases the traffic load. In many cities, the construction of bus sites is seriously inadequate, the density of bus network and the coverage rate of bus stations are low, and the pace of bus lane construction is slow. In some small and medium-sized cities, due to the poor accessibility of public transport, low coverage of public transport service facilities and poor bus condition, the proportion of public transport trips is low, which seriously restricts the healthy development of cities.
1.5 The quality of public transport services is not high.
The service provided by public transport is not humanized enough, such as passengers’ failure to get accurate information of bus arrival, unreasonable equipment setting on the bus, poor riding environment, poor service awareness and attitude of drivers and passengers, which directly leads to passengers’ low satisfaction with public transport.
2. Measures to increase the proportion of public transport trips
2.1 Moderately restrict personal transportation and encourage the development of public transportation.
Private cars are required to make way for buses in certain periods and sections, which is an indispensable part of the bus priority development strategy.
2.2 Set up bus lanes to improve the speed of bus operation.
Taking the construction of public transport road system as the focus of short-term construction, combining the transformation of the old city and the improvement of the road network, widening some branches as public transport roads; Combined with one-way traffic organization, provide reverse bus lanes; Set up bus lanes for peak hours; Bus lanes are set up in some sections, and bus lanes are built by using a wide central partition; At intersections where conditions permit, special bus entrance lanes or bus advance parking zones are set at intersections. In the urban road network, when choosing the road with bus priority lane, we should mainly pay attention to several factors such as passenger flow, bus flow and its speed. We should choose a section with a large passenger flow, a large bus flow (more than 150 one-way buses in peak hours) and a low bus speed. At the same time, the implementation of bus priority lanes is also limited by road conditions and traffic conditions. Generally speaking, only roads with six lanes (or more) in both directions and no less than four lanes in and out of intersections can be equipped with dedicated lanes. It is suggested that cities that newly set up dedicated lanes should first consider the main bus and passenger corridors with good road conditions, and should be piloted before promotion. We should consider the impact of setting bus lanes on other traffic, and make a special analysis and evaluation to reduce the negative effects caused by setting bus lanes. Bus lanes should be equipped with perfect signs, markings and other identification systems to be clear and intuitive. It is necessary to strengthen publicity, education and monitoring to ensure that public transport roads are inviolable and truly dedicated. To establish a monitoring system for public transport lanes,Social vehicles that occupy special lanes and interfere with the normal operation of public transport should be dealt with severely.

Figure 2-1 Bus Lane
2.3 Optimize bus lines and station settings to shorten traffic time.
2.3.1 Reasonable determination and timely adjustment of the length of public transport lines.
General public transport routes are from one suburb of the city to the other, and the selected route should have a large passenger flow as much as possible, and the shortest route should be determined on this basis. Most public transport lines in urban areas are opened along the road system, forming a public transport line network. Bus lines and stops should extend to urban functional areas such as residential areas, commercial areas and school gathering areas as far as possible to facilitate people’s production and life. The layout of public transport lines should have a range of the number of lines, that is, the road network of public transport lines should not be set too thinly, and lines should not be opened as long as residents have the requirements of riding. The length of the line should be within the specified range, which is convenient for the organization and management of the bus system itself. The line is too long and the vehicle turnover time is too long, which will reduce the punctuality rate of vehicles and make it difficult to start and allocate vehicles; The line is too short, the vehicle turnover is too fast, the passenger flow may be insufficient, the transportation efficiency of the bus can not be fully exerted, and the economic benefit is not high. Therefore, when setting up the bus line, the length of the generated line should be kept within a certain range as far as possible. Generally speaking, the length of the line should be 30-40min, and the shortest is 20min. For small and medium-sized cities, the longest is 45min, and for big cities, it is 60min. Therefore, for the bus lines with an average operating speed of 15km/h, the shortest restricted distance is 5km, and the longest restricted distance is 11.25km (small and medium-sized cities) and 15km (big cities). If the length of the alternative line is greater than the longest limit distance or less than the shortest limit distance, the line setting is generally not considered.
2.3.2 Line network density affects the convenience of passengers’ travel.
Too high or too low line network density will lead to an increase in non-vehicle travel time (waiting time and walking time). It is necessary to consider the indicators of control planning according to the facts. Generally, the planning indicators include road network density, line length, non-linear coefficient of route and average travel time of bus passengers. The average travel time of passengers reflects the overall situation of urban public transport services, and the shorter the average time, the better the overall situation. Only by considering these indicators as a whole and rationalizing them can we actually facilitate passengers’ travel.
2.3.3 Set up the site scientifically
Station layout will affect the transfer distance and time of passengers. When setting bus stop spacing in China, it is usually based on the fact that residents’ walking distance is not more than 300m, and the general stop distance is 500-600m m. Small buses can set shorter stop spacing, so it is recommended to use harbor-type stops. Bus stops should be located near residential areas, commercial areas or cultural and sports centers with relatively concentrated entrances and exits, and near major passenger distribution points; No bus stops should be set near the level crossing, and stops should be set in residential areas with a scale of 30,000 to 150,000 people, which are 300m away from the level crossing and 500m away from the overpass or bridge slope. The carrying capacity of the station is 500-1200 person-times/peak hour; The service radius of the station is 95% of the passengers who get on the bus within its service radius of 350m; The passenger transport capacity adapts to the passenger transport demand; The scale of the station is suitable for the number of operating vehicles. Then, the distribution of existing sites is analyzed and adjusted and supplemented accordingly. When the passenger traffic is more than 500 passengers/peak hour, additional stations are needed; On the road section, the transfer distance in the same direction should not be greater than 50m, the transfer distance in the opposite direction should not be greater than 100m, and the transfer distance at the level interchange should not be greater than 150m and 200m. The service capacity is calculated by the radius of the station service area coverage of 300m ≥ 50%, 500m radius calculation ≥ 90%。 In addition to the prescribed routes, there can also be various supplementary routes such as night routes, commuting to and from peak-hour line, special tourist routes, special holiday routes and minibus routes that can pass through small streets and lanes.Attract people to use public transport.
2.4 Give priority to signals and shorten the delay time at intersections.
Road intersections should provide extended passing signals for buses to shorten the stop signal time, and timely adjust the intersection signal display period according to the actual operation situation of buses on each line and the requirements of transportation time, realize dynamic management of traffic signals, or activate the green light when a bus arrives at a signalized intersection. At intersections with single traffic mode and traffic flow direction, the bus signal priority should be implemented first, and the "green wave belt" of bus lines should be implemented in conditional sections to ensure the exclusive or priority use of public transport vehicles on the road. It can also be required that ordinary traffic should give priority to the bus when it enters the traffic flow from the station, thus reducing the delay. By establishing the best signal control system that matches the bus speed, the delay time of buses on roads and intersections can be reduced. A common practice is to install a special signal transmitter with a fixed frequency on the bus, and set a signal detector with a corresponding frequency on the road. The detector is connected with the traffic signal controller. When the bus approaches the entrance of the intersection, the green light signal is advanced or extended through the communication between the vehicle and the roadside controller (radar or infrared method is mostly used at present) to make the bus pass first, and the signal parameters are changed accordingly. This method is called passive priority control. There is also the use of special traffic lights for buses or the adjustment of signal period and phase according to the traffic volume of buses to reduce the parking time of buses at intersections, which is called active priority control.

Figure 2-2 BRT special signal lamp
2.5 building a high-tech bus rapid transit system to make public transportation more economical and efficient.
High-tech Bus Rapid Transit System (BRT) is the "third way" between the traditional rail mode and the bus mode, which is established on the basis of bus lanes, and can even be said to be a bridge between them. It provides a more economical and quick method for urban planners to improve the level of traffic services. High-tech Bus Rapid Transit System (BRT) is as efficient as subway, but its construction cost is only 5% of that of subway. In other words, the funds needed to build a 1 km subway line can build a 10-20 km BRT network. A perfect BRT network often plays a more important role in the whole urban public transport than a rail transit corridor. According to experts, the investment of large-capacity bus system is about 200 million yuan to 100 million yuan per kilometer, which is far lower than that of subway. However, judging from the passenger transport capacity, the large-capacity bus system is basically the same as the light rail, which is 1/3 to 1/2 of the subway. Judging from the running speed of the system, the speed of large-capacity bus system and light rail is 10 to 20 kilometers per hour, which is about 1/3 to 1/2 of the running speed of subway. Judging from the construction period, the large-capacity public transport system is the shortest, generally in one to two years. Large-capacity public transport system has incomparable advantages in terms of construction period, construction cost and service level, which is in line with the construction needs of modern metropolis. In recent years, the city of Los Angeles in the United States stopped its massive rail transit construction and used the funds to build the urban bus rapid transit network.
At present, the promotion of BRT system in China is of great strategic significance to reduce the financial burden of the city and the travel expenses of residents.
(1) Fast and punctual — — Dedicated lanes can ensure that vehicles are not disturbed by traffic jams, thus ensuring the punctuality and punctuality of driving time;
(2) Safety and comfort — Dedicated lanes can ensure driving safety more effectively, and new large-capacity public transport vehicles can improve comfort;
(3) BRT system fully embodies the principle of bus priority, ensures that public transportation takes up enough road resources and sufficient investment, truly realizes the optimal allocation of traffic resources, and embodies the principle of equality before the right of way.

Figure 2-3 Bus Rapid Transit (BRT)
2.6 the establishment of intelligent public transport management system, all-round optimization of traffic time
Intelligent public transport system is based on the research of key basic theories such as public transport network distribution and public transport dispatching, and uses the theory and method of system engineering to integrate modern communication, information, electronic control, computer, network, GPS, GIS and other high and new technologies into public transport system, and through the establishment of intelligent dispatching system, informationization, modernization and intelligence of operation and management, Through multimedia (such as TV, radio, interactive consulting terminal, Internet, etc.) to provide travelers with public transportation information before and during the trip, and implement intelligent multi-angle system of public transportation, we can provide travelers with optimal bus operation speed, departure interval, road network setting, etc., so as to attract the public to travel by bus, alleviate urban traffic congestion, effectively solve urban traffic problems and create greater social and economic benefits.

Figure 2-4 Structural Framework of Intelligent Public Transport System

Figure 2-5 Intelligent Bus Management System
2.7 Directional development of public transport
Expand the scope of urban planning from residential areas and neighboring blocks to regions and regions, and strive to form a small and compact city with convenient public transportation. Its basic idea is: "Commercial facilities, houses, work units and public facilities can be walked from public transportation stations." Urban planning is guided by land use, and transportation system planning depends on the output of land use model. The core idea is the layout mode of public transportation corridor as the development axis and bus stops as nodes, and land development is concentrated at each node. This is a mixed development that integrates the functions of residence, work and business, and these nodes are within walking distance.

Figure 2-6 Schematic Diagram of Public Transport Oriented Development Zone
2.8 improve the conversion efficiency between public transport.
Urban public transport transfer system connects different modes of urban passenger transport, which provides connecting services for residents to use public transport. With the large-scale construction of mass transit facilities such as rail transit in Chinese cities, it is of great significance to improve the conversion efficiency of urban public transport.
2.9 government macro-control, to create a bus price advantage
Increase financial subsidies for public transport, establish a fare floating mechanism, establish a special tax policy, and use transfer tickets and preferential tickets.
2.10 Improve the comfort of public transportation and provide humanized services.
Other things being equal, people will choose the most comfortable mode of transportation, and the degree of comfort is closely related to the travel distance and the degree of congestion. The degree of congestion in the car can be adjusted by adjusting the appropriate bus operating speed and departure interval. The poor service quality of a public transport enterprise will lead to fewer people choosing public transport, which will affect the benefits of the enterprise. The poor benefits of the enterprise will make the service quality even more difficult to mention, and fewer people will choose public transport, forming a vicious circle. In this way, providing humanized quality service is also an important link to increase the comfort of public transportation.
References:
[1] "Discussion on the Development Strategy of Urban Public Transport" by Cai Mingzhu
[2] "Urban Public Transport Network Optimization" by Chen Qixin.
[3] "On the Priority of Urban Public Transport" by Xu Xingjun
[4] "Exploring how to improve the sharing rate of urban public transport" by Xin Xiaomin.
Source: Jiangxi Tonglian Written by Zhao Qi






















































