CE 452 Traffic Impact Assessment 1 Why Required? New developments Produce/ attract new traffic Production: Residences Attraction: Shops, Offices, Schools, Hospitals etc. etc. Changes in traffic pattern Mode diversions Route diversions Peaking time, etc. 2 1
Why Required? Any large land development near major junctions and/or major urban arterials requires careful investigation of the access facilities to and from adjacent roadways The evaluation of any negative traffic impacts must be carefully reviewed and if necessary, mitigation strategies must be implemented to ensure trouble free traffic operations in and around such a development Safe and smooth traffic operations in and around commercial developments are not only essential for the community at large, but are also critical for a development to succeed 3 Traffic vs. Transport Impact Assessment Source: http://www.planningni.gov.uk/ 4 2
When Required? When a specified area is being rezoned When development elopment involves a specified number of dwelling units or floor space When development occurs in a sensitive area (e.g. near major intersections, critical business district, area already having traffic problems, etc.) When financial assessments are required and the extent of impact must be quantified 5 Whose Responsibility? Should be a requirement of the City Planning Authority as a pre-requisite iit for project approval (similar to EIA) Can be performed directly by the City Planning Authority or contracted to consulting companies Recommendations can be implemented on public-private partnership framework 6 3
Example: Jamuna Future Park 7 Steps of Traffic Impact Assessment (TIA) 1. Determination of scope of work 2. Data collection a. Pi Primary data b. Secondary data 3. Analysis a. Required road width and intersection capacity b. c. Required parking facilities Required loading and unloading facilities 4. Recommendations a. Compare against provided facilities b. Provide remedial measures if required 8 4
1. Determination of Scope of Work Identify areas likely to be significantly affected Generally based on the jd judgment of the analyst 9 2. Data Secondary Details of the proposed development Exact location of the project Floor area and land use Inventory of provided facilities Established rates for generation and attraction (to be provided) 10 5
2. Data Primary Network, geometric and traffic control data within the influence area including pedestrian facilities Existing traffic flow: Traffic flow volume, OD, directional movements, speed, parking inventory, etc. Predicted traffic: Traffic flow volume, OD 11 3. Analysis Calculate Required road width and intersection capacity Four-step model Analogy method Required parking facilities Required loading and unloading facilities 12 6
4. Recommendations Compare required vs. existing (or expanded ) Roadway and intersection i capacity Parking facilities Provide remedial measures if required 13 Example: Andalusia Project, Jeddah, KSA Consultant: MODON, Jeddah Year: 2007 Courtesy: Dr. Tanweer Hasan 14 7
-- Background The Kinan International for Real Estate Development Company has initiated its Andalusia project in Jeddah, Kingdom of Saudi Arabia. The project includes offices, apartments, hotel, and retail shops. Modon, a local transportation consulting firm, is hired to evaluate the traffic impact of the proposed development project and to recommend mitigation strategies, as necessary. 15 --Project Site The project is located in the north-east corner of the Tariq Bin Zeyad intersection of Al Andalus Street and King Abdullah Road. The intersection is a roundabout and is also known as ship roundabout. The project site is surrounded by two major arterials- Al- Andalus Street on the west and King Abdullah Road on the south. While there is a narrow road on the east side (back of the project), there are some private corporate buildings and government offices on the north of the project site. 16 8
--Project Site 17 --Project Site The access to the project site from west (front) is through the service road of Al-Andalus Andalus street. To access the service road of Al- Andalus street, one needs to use the service road of King Abdullah road. The people can enter the project site from the back using the inner circulating streets. Project Site Plan 18 9
--Study Objectives The following objectives were established for the study: 1. Analyzing the current traffic situation in the study area on the basis of the volume of traffic and the level of service on the identified streets and the surrounding intersections during the peak hours. 2. Estimating the future traffic volume generated from the project during the peak and non peak hours. 3. Distributionib i of these traffic volumes on the surrounding road network. 19 --Study Objectives 4. Analysis of the level of service of the selected intersections in the study area to assess the future state of traffic flow when the project is open and suggest remedial measures. 5. Study the proposed street network including the intersections, roundabouts, entrances and exits to the project site and suggest solutions to facilitate smooth and safe movements of traffic. 6. Estimating the parking demand for the project in order to assess the adequacy of the proposed parking spaces. 7. Suggest possible solutions for the existing surrounding road network in-terms of geometric and operational improvements for smooth and safe flow 20 of traffic. 10
--Defining the Study Area Considering the possible impacts of the trips coming into and exiting from the project, the study area was defined as follows: North side- section between the intersection of Al- Andalus and Maadi and the intersection of Maadi and Hail East side- section between the intersection of Maadi and Hail and the intersection of Hail and Amanah South- section between the intersection i of Hail and Amanah and the intersection of Al-Falah and Amanah West- section between the intersection of Al-Falah and Amanah and the intersection of Al-Andalus and Maadi. 21 --Defining the Study Area Study Area 22 11
--Defining the Study Area A total of eight intersections are selected which are expected to be affected by the traffic generated by this new development. Intersection No. Intersecting Streets 1 Al-Andalus Andalus Street and Maadi Street 2 Maadi Street and Fayeed Ur Rahman Street 3 Maadi Street and Hail Street 4 Hail Street and King Abdullah Road 5 King Abdullah Road and Al-Andalus Street 6 Fayeed Ur Rahman Street and Fayeed Al Muhabba Street 7 Fayeed Ur Rahman Street and Fayeed Al Karam Street 8 Al-Falah Street and Amanah Street 23 --Data Collection and Analysis The data collected are of two types: Office Data: include base maps of the study area, the architectural plans showing the layouts of the different components of the project, the digitized drawings of the street networks within the study area, and historic data on some streets within the study area. The historic data was used to determine the natural growth of traffic in the surrounding areas of the project. Field Data: include roadway data- number of lanes, width of each lane, width of the median, exclusive turning lanes, shoulders, etc.); control condition data- whether the intersection is signalized or not, determining the cycle time, phases, etc, and traffic datamidsection traffic volume as well as turning proportions at the study intersections. 24 12
--Data Collection and Analysis Automatic and Manual counting techniques are used to collect traffic volume data at midsections and at the study intersections, respectively. Automatic counting period was continuous count for seven full days in a week. The manual counting (3 hours during the peak period) was adopted to determine the turning proportion of traffic at all approaches of the study intersections. 25 --Data Collection and Analysis Automatic Counting Locations: Station Location 1 On Al-Andalus (North of Andalus and Maadi) 2 On Maadi (West of Maadi and Fayeed Ur Rahman) 3 On Hail (North of Hail and King Abdullah) 4 On King Abdullah (East of King Abdullah and Al- Andalus) 5 On Falah (South of Falah and Amanah) 6 On Amanah (West of Falah and Amanah) 7 8 9 On Al-Andalus (South of King Abdullah and Al- Andalus) On Al-Andalus (North of King Abdullah and Al- Andalus) On Fayeed Ur Rahman (North of King Abdullah Service Road and Fayeed Ur Rahman) 26 13
--Data Collection and Analysis Daily Traffic Volumes on Streets within Study Area: 27 --Data Collection and Analysis A.M. Peak Hour Traffic Volumes on Streets within Study Area: 28 14
--Data Collection and Analysis P.M. Peak Hour Traffic Volumes on Streets within Study Area: 29 --Data Collection and Analysis Manual Counting Locations: Intersection No. Intersecting Streets 1 Al-Andalus Andalus Street and Maadi Street 2 Maadi Street and Fayeed Ur Rahman Street 3 Maadi Street and Hail Street 4 Hail Street and King Abdullah Road 5 King Abdullah Road and Al-Andalus Street 6 Fayeed Ur Rahman Street and Fayeed Al Muhabba Street 7 Fayeed Ur Rahman Street and Fayeed Al Karam Street 8 Al-Falah Street and Amanah Street 30 15
--Data Collection and Analysis Traffic Volumes at Andalus & Maadi Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (Andalus) 1971 325 481 162 2939 Southbound (Andalus) Eastbound (Maadi) 1889 285 483 211 2868 146 142 352 7 647 5:00-6:00 PM Westbound (Maadi) 227 178 230 120 755 31 --Data Collection and Analysis Traffic Volumes at Maadi & F. Rahman Intersection: Peak Hour Turning Proportion (veh/h) Approach Through Right Left U Total Peak Hour Northbound (F. Raham) 0 237 0 0 237 Eastbound (Maadi) 1212 252 0 0 1464 5:00-6:00 PM Westbound (Maadi) 0 0 0 0 0 32 16
--Data Collection and Analysis Traffic Volumes at Maadi & Haail Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (Hail) 1048 0 300 61 1409 Southbound (Hail) Eastbound (Maadi) 0 0 0 0 0 0 492 386 107 985 4:45-5:45 PM Westbound (Maadi) 95 414 250 0 759 33 --Data Collection and Analysis Traffic Volumes at Haail & King Abdullah Rd. Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (Hail) 703 322 222 12 1259 Southbound (Hail) 466 115 555 39 1175 Eastbound (King Abdullah) 0 297 326 181 804 5:00-6:00 PM Westbound (King Abdullah) 0 586 474 522 1582 34 17
--Data Collection and Analysis Traffic Volumes at King Abdullah Rd. & Andalus Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (Andalus) 2870 352 0 134 3356 Southbound (Andalus) 1349 120 1102 164 2735 Eastbound (King Abdullah) 0 168 0 0 168 5:00-6:00 PM Westbound (King Abdullah) 0 491 1553 108 2152 35 --Data Collection and Analysis Traffic Volumes at F. Rahman & F. Muhabbah Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (F. Rahma) 38 8 4 2 52 Southbound (F. Rahma) 27 26 73 10 136 Eastbound (F.Muhabba) 31 1 6 0 38 4:30-5:30 PM Westbound (F.Muhabba) 28 11 9 0 48 36 18
--Data Collection and Analysis Traffic Volumes at F. Rahman & F. Karam Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (F. Rahma) 72 24 9 19 124 Southbound (F. Rahma) Eastbound (F. Karam) 45 16 146 40 347 20 5 23 0 48 4:45-5:45 5:45 PM Westbound (F. Karam) 28 97 31 3 159 37 --Data Collection and Analysis Traffic Volumes at Al-Falah & Amanah Intersection: Approach Peak Hour Turning Proportion (veh/h) Through Right Left U Total Peak Hour Northbound (Andalus) 2472 186 883 30 3571 Southbound (Andalus) Eastbound (Amanah) 1757 319 238 51 2365 167 1026 219 8 1420 500600PM 5:00-6:00 Westbound (Amanah) 138 591 383 38 1150 38 19
-Tools Used for Analyzing Traffic Operating Conditions Traffic analysis is carried out using one of the well known analytic software, Synchro and SimTraffic package software popularly l known as 'SYNCHRO' version number 6.0, taking into consideration the local traffic situations including the drivers characteristics and the road circumstances. Necessary changes were done to the software to represent the local conditions as close as possible. Synchro is a complete software package for modeling and optimizing traffic signal timings. Synchro provides an easy-to-use solution for single intersection capacity analysis and timing optimization. 39 -Tools Used for Analyzing Traffic Operating Conditions Delay calculations are an integral part of the optimization objective. All values are entered in easy-to-use forms. Calculations and intermediate results are shown on the same forms. Synchro is fully interactive, when the input values are changed, the results are updated automatically. Timing plans are shown on easy to comprehend timing diagrams. The vehicle flow is animated and shows individual vehicles that stop, queue up, and then go. 40 20
-Tools Used for Analyzing Traffic Operating Conditions The assessment of traffic operating conditions at the study area were done at two levels- the total study area street network as a whole and each of the eight study intersections. The traffic parameters used as measures of effectiveness are: Delay experienced by the vehicles Level of service (LOS) Traffic density Traffic flow Speed Travel time Number of stops, and Stop time 41 -Tools Used for Analyzing Traffic Operating Conditions Volume Input Window Phase Timing Input Window 42 21
-Tools Used for Analyzing Traffic Operating Conditions LOS Output Window Flow Animation Output Window 43 -Estimation of Traffic Demand of the Project The project is likely to generate significant amount of trips during the peak hours. Since this is a mixed used development (see the table below), both production and attraction of trips will occur. Trips produced in the project area will have their destinations in other parts of the city, and trips attracted to the project site will have their destinations at the project site. 44 22
-Estimation of Traffic Demand of the Project The four-step transportation modeling techniques are used. Since the trips generated at the project site are vehicle trips (using passenger vehicles), the mode choice step is absent. The steps followed for the demand estimation and for the determination of the additional turning traffic volume at the study intersections are: Estimation of trip generation at the project. Distribution of these trips among all the city districts and zones. Assigning these trips to the city and study area street network to determine the traffic volume at the study intersections. 45 -Estimation of Traffic Demand of the Project Trip rates for different types of land uses within the project area were carefully selected so that they represent the local conditions. Several international publications as well as local trip generation study results were reviewed in this regard. The calculations showed that the project will generate 4,757 trips during the evening peak hour of which 1,739 trips are incoming and 3,018 trips are exiting. 46 23
-Estimation of Traffic Demand of the Project Trip Generation at the Project Site Peak Hour Trips Generated by the Project (Number of Vehicle Trips per Hour) Land Use A.M. Peak P.M. Peak IN OUT IN OUT Office 2,165 541 492 1,968 Residential 238 357 336 224 Hotel 116 94 70 50 Retail 231 231 841 776 Total 2,750 1,223 1,739 3,018 Grand Total 3,973 4,757 47 -Estimation of Traffic Demand of the Project To facilitate the trip distribution modeling, the city of Jeddah was divided into 19 Traffic Analysis Zones (TAZs). A simple gravity model was used to distribute the trips. Travel time between each TAZ and the site was used to calculate the travel friction between each zone and the project site. The traffic assignment was done assuming that the travelers will choose the minimum time paths. 48 24
-Estimation of Traffic Demand of the Project The results of the assignment showed that 40% of the total trips generated at the project site have their origins or destinations in the north. The corresponding figures for south and east are 22% and 38%, respectively. The resulting (project- generated) turning traffic volumes at the eight study intersections are also estimated to assess the future traffic conditions. 49 -Assessment of Traffic Operating Conditions Ten (10) scenarios were analyzed and simulated using the Synchro and SimTraffic package software: R1: Existing condition of the network (2007). R2: Future condition of the network considering only the natural traffic growth (2012). R3: Future condition of the network considering only the natural traffic growth (2017). R4: Scenario R2 plus the impact of this project. R5: Scenario R3 plus the impact of this project. R6: Scenario R4 plus Alternative No.1 of the suggested improvements. R7: Scenario R4 plus Alternative No.2 of the suggested improvements. R8: Scenario R6 plus R7. R9: Scenario R5 plus Alternative No.1 and Alternative No.2 of the suggested improvements. R10: Scenario R9 plus Alternative No.3 of the suggested improvements. 50 25
-Assessment of Traffic Operating Conditions Three Alternatives included in scenarios R6 through R10 are: Alternative No. 1: provide a one way connection from the service road of King Abdullah Road and the street bordering the project from the east side. In addition to that the street bordering the project from the east side needs to be widened to facilitate circulation of the project traffic, especially the exiting traffic. 51 -Assessment of Traffic Operating Conditions Three Alternatives included in scenarios R6 through R10 are (cont.): Alternative No. 2: Jeddah Municipality is planning to upgrade Al-Andalus Street to be a limited access highway which will be accomplished at Tareek Ben Zeyad Roundabout db through h the construction of an underpass along this street in the North- South direction. 52 26
-Assessment of Traffic Operating Conditions Three Alternatives included in scenarios R6 through R10 are (cont.): Alternative No. 3: Since both King Abdullah Road and Al-Andalus Street will be limited access highways, this will require adding directional ramps to take the left turning movements as free movements. This study is recommending to have a directional ramp to take the left turning traffic from Al-Andalus Street to King Abdullah Road. The left turning traffic from King Abdullah Road to Al-Andalus Street will also have an at-grade exclusive lane through the roundabout. 53 -Assessment of Traffic Operating Conditions The results of the evaluation of the traffic operating conditions are presented in the following slides. The results include ld the performance of the network as a whole and also the performance of each study intersections. The performance was measured in terms of delays experienced by the vehicles, levels of service, and a performance index which is a function of delay, number of stops, travel time, travel speed, etc. Note that a higher value of performance index indicates a worse condition. 54 27
-Assessment of Traffic Operating Conditions Network Performance for Different Scenarios- Do Nothing. Scenarios Measures of Effectiveness R1: Existing 2007 R2: 2012 only natural growth R3: 2017 only natural growth R4: 2012 growth and project R5: 2017 growth and project Delay/Veh Total Delay Performance Index 20 44 68 59 95 435 1172 2293 1815 3723 500.5 1249.5 2388.2 1914.1 3845.2 Higher value indicates worse condition 55 -Assessment of Traffic Operating Performance Conditions No Network Performance Index 1 R1: Existing condition of the network 2007 500.5 Network Performance Index (higher value indicates worse condition) for All Scenarios 2 R2: Future condition i of the network with only the natural traffic growth 2012 1249.5 3 R3: Future condition of the network with only the natural traffic growth 2017 2388.2 4 R4: Scenario R2 plus the impact of this project. 1914.1 5 R5: Scenario R3 plus the impact of this project 3845.2 6 7 R6: Scenario R4 plus Alternative No.1 of the suggested improvements R7: Scenario R4 plus Alternative No.2 of the suggested dimprovements 1827.9 1685.0 8 R8: Scenario R6 plus R7 1682.3 9 10 R9: Scenario R5 plus Alternative No.1and Alternative No.2 of the suggested improvements R10: Scenario R9 plus Alternative No.3 of the suggested improvements 3749.5 1190.7 56 28
-Assessment of Traffic Operating Conditions Int. No.8: Al Falah & Amanah Delay (sec/veh) 100 150 200 0 50 250 300 350 R1: Existing condition of the network (2007). 92 R2: Future condition of the network with only the natural traffic growth (2012). R3: Future condition of the network with only the natural traffic growth (2017). Scenarios R4: Scenario R2 plus the impact of this project. R5: Scenario R3 plus the impact of this project R6: Scenario R4 plus Alternative No.1 of the suggested improvements R7: Scenario R4 plus Alternative No.2 of the suggested improvements R8: Scenario R6 plus R7 R9: Scenario R5 plus (Alternative No.1and Alternative No.2 of the suggested improvements 170 173 173 173 173 292 293 293 R10: Scenario R9 plus Alternative No.3 of the suggested improvements 6 57 -Assessment of Traffic Operating Conditions In 2017 due to the natural growth of traffic, except the Fayeed Ur Rahman and Fayeed Al Muhabbah intersection, seven other study intersections will be operating at beyond their capacity (i.e., LOS F). The impact of the project on the surrounding area is significant. In 2017, considering the impact of the project and the natural growth of traffic, the intersections those are most affected (as compared to the existing condition) are the three intersections on Fayeed Ur Rahman street- intersections number 2, 6, and 7. This is because the entering and exiting traffic from the project will be using the streets behind (east side) the project. 58 29
-Assessment of Traffic Operating Conditions The total network delay will increase, due to both natural growth and project generated traffic, from 435 hours in 2007 to 3723 hours in 2017, which is an increase of more than eight times. The performance of the network, measured by the performance index, showed that the network performance will deteriorate by more than seven times (500.5 in 2007 as compared to 3845.2 in 2017). 59 -Assessment of Traffic Operating Conditions Alternative No. 1 (widening of the street bordering the project in the east side and a direct access to the project site from the service road of King Abdullah Road) cannot improve the traffic operating condition at the major intersections in the study area. Alternative 1, however, could improve the quality of traffic flow of the three minor intersections in the back of the project on Fayeed Ur Rahman street (delay at Maadi and Fayeed Ur Rahman intersection reduced from 26 sec/veh to 22 sec/veh, and delay at Fayeed Ur Rahman and Fayeed Al Muhabbah intersection reduced from 22 sec/veh to only 9 sec/veh). This Alternative could also increase the network performance by 4.5%. 60 30
-Assessment of Traffic Operating Conditions Implementation of Alternative 1 and Alternative 2 in 2012 can improve the quality of traffic flow on Fayeed Ur Rahman and at the Tarik Bin Zyead roundabout with a consequent 12.5% increase in network performance. The network performance in 2017 can be significantly increased if Alternative 3 along with the other two alternatives are implemented. The analyses showed that the network performance could be increased by more than three times as compared to the network performance in the same year when nothing is done (while performance index for scenario R5 is 3845.2, the performance index for scenario R10 is only 1190.7). 61 -Parking Requirements The standard parking requirements according to Local Governorate Plan 1427 H for different types of land uses are: Land Use Parking Requirements Area Type Apartments 1 car/150 m 2 or 1 car per unit, whichever is higher Leasable Offices 1 car/60 m 2 Gross Mall and Supermarkets 1 car/25 m 2 Leasable Hotels 1 car/60 m 2 Gross 62 31
-Parking Requirements Adequacy of the Number of Parking Spaces for Different Land Uses in the Project. Land Use Area (m 2 ) Number of Parking Spaces Required Parking Spaces Provided in the Design Apartments 56000 Leasable; 400 units 400 459 Offices 123000 Gross 2050 2080 Mall and Supermarkets 23100 Leasable 500 200 Hotels 30000 Gross 924 750 Total 3874 3489 63 -Parking Requirements Numbers of parking spaces provided for the apartments (459) and office areas (2080) are more than the standard requirements of 400 and 2050, respectively. The numbers of parking spaces provided for the shoppers (750) are a little lower than the standard requirement of 924 parking spaces. The number of parking spaces provided for the hotel (200), however, is considerably less than the standard requirement of 500 parking spaces. The comparison shows that there is a total deficiency of 385 parking spaces (3874 required, 3489 provided). 64 32
-Parking Requirements The project is a mixed-use development. The peak hours of the shopping trips occur in the late evening when most of the offices are closed. Sharing the office parking spaces can easily solve the total parking deficiency of retail and hotel (474) which is only 23% of the 2080 parking spaces provided for the office. Therefore, the parking spaces provided in the project should be sufficient to meet the total parking demand. 65 -Study Recommendations It is recommended that the Andalusia Project proposal submitted by Kinan International should be approved. The following network improvement measures, however, are also recommended to be implemented during a time period of 10 years (from 2007-2017): The road bordering the project in the east side should be widened by 5 meters to a total width of 20 meters to facilitate better circulation of traffic. Provideaccess(entry)totheprojectinthesouthsideso that the project traffic can enter directly from the service road of King Abdullah Road. 66 33
-Study Recommendations Construct an underpass (tunnel) on Al-Andalus Street at Tarik Bin Zyead roundabout to preserve the mobility function of this major arterial in future. When the tunnel is constructed, the intersection of Andalus & Maadi, and intersection of Amanah & Al Falah must be closed. Construct directional ramps at Tarik Bin Zyead roundabout db to facilitate the movements of lf left turning traffic from Andalus Street to King Abdullah Road and also from King Abdullah Road to Andalus Street. 67 Assignment Perform a Traffic Impact Assessment (TIA) of the New Pl PalasiMarket to be constructed near BUET Campus 68 34
Tasks Perform a Traffic Impact Assessment (TIA) of the New Palasi Market to be constructed near BUET Campus. You need to perform the following tasks: Reconnaissance survey to evaluate existing conditions Data collection Secondary (will be provided) Primary (to be collected) Analysis in analogy method (hint: from where people will come, through which roads, how many additional vehicles, etc.) Recommendations 69 Presentation and Report Background of the project Importance of TIA for this particular location Analysis results by analogy method Existing geometric, parking and traffic data Predicted traffic and parking requirements Recommendations (hint: are the existing roadway and parking capacities sufficient ffii to meet the demands, d if not make proposals that can help in overcoming potential problems) 70 35