Transport Modes and Technologies A Walking Tour on Capacity, LOS Urban Transportation Planning MIT Course 1.252j/11.380j Fall 2006 Mikel Murga, MIT Research Associate
Transport Modes and Technologies Private Transport: The automobile Collective Transport Bus Light Rail Rapid Transit Taxi, CarSharing Non Motorized Modes Walking Biking 2
The Automobile - Infrastructure Road system: Hierarchical system: From turnpike to local street From unimpeded movement to access to properties (Mobility vs Accessibility in their lingo) Uninterrupted segments: Turnpike with access control Interrupted segments: Traffic signals, stops Mobility Land Access Arterials Collectors Locals Figure by MIT OCW. 3
The Automobile Capacity The capacity of a facility is the maximum hourly rate at which persons or vehicles reasonably can be expected to traverse a point or a uniform section of a lane or roadway during a given time period under prevailing roadway, traffic, and control conditions Highway Capacity Manual Transportation Research Board (TRB) HCM2000 4
Density Speed Relationship S f =Free flow speed S o =Optimum speed S f D o =Optimum density D j = Jam density Speed (mi/h) S o Oversaturated Flow 0 D o Density (veh/mi/ln) D j Speed-Density Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 9
Speed-Flow Relationship S f =Free flow speed S o =Optimum speed S f D o =Optimum density D j = Jam density V m = Maximum Flow Speed (mi/h) S o Oversaturated Flow D j D o 0 Flow (veh/h/ln) V m Speed-Flow Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 10
Flow-Density Relationship S f =Free flow speed S o =Optimum speed S o D o =Optimum density D j = Jam density Flow (veh/h/ln) V m S f Oversaturated Flow V m = Maximum Flow 0 D o D j Density (veh/mi/ln) Flow-Density Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 11
Speed-Flow-Density Relationship S f S f =Free flow speed S o =Optimum speed D o =Optimum density D j = Jam density Speed (mi/h) S o 0 S o 0 Flow (veh/h/ln) V m D o V m = Maximum Flow V m D=v/S Flow (veh/h/ln) 0 D o Density (veh/mi/ln) D j Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 12
The Automobile Capacity Vehicle throughput in uninterrumpted flow: Speeddensity curves 120 100 80 60 40 FFS = 120 km/h 110 100 90 LOS A Density = 7 pc/km/ln 1300 11 16 22 28 1450 1600 1750 B C D E 20 Note: FFS= Free-flow speed 0 0 400 800 1200 1600 2000 2400 Flow Rate, v (pc/h/ln) p Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 13
Speed-Flow Curves: HCM speed-flow curve, before and after: Human adaptation to driving in congested conditions The original dream of ITS BASE FREEWAY SEGMENT Average Travel Speed (MPH) 60 50 40 30 20 10 0 8-Lanes 2 (0.1) 4-Lanes 4 (0.2) 6 (0.3) Design Speed 8 (0.4) 60 MPH 10 (0.5) 50 MPH Unstable Flow 12 (0.6) 14 (0.7) 70 MPH 16 (0.8) Vol/ln (100 pcphpi) v/c Ratio** *capacity **v/c ratio based on 2000 pcphpi valid only for 60- and 70-MPH design speeds *1900 pcphpi 18 (0.9) *2000 pcphpi 20 (1.0) Average Passenger-Car Speed (mph) 80 60 40 20 0 A 0 400 Flow-Flow Speed (mph) > 70 65 60 55 10 16 24 32 1300 1450 800 1200 Flow Rate (pcphpl) 1600 1750 B C D E Capacity (pcphpl) 2400 2350 2300 2250 45 pcpmpl 0 1600 2000 2400 14 120 80 40 Note: Capacity varies by free-flow speed. Average Passenger-Car Speed (km/h) Figures by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 14
Speed-Flow Curves Urban Transportation Planning Fall 2006 Unstable Flow Stable Flow Flows (Vehicles/hour/lane) 2500 2000 1500 1000 500 Toll Range Undersaturated Oversaturated Shock Wave Density at Flow Capacity Flow at the bottleneck 0 0 20 40 60 80 100 120 Density (Vehicles/km/lane) Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 15
From ideal capacity to Different vehicles have different power to weight ratios, therefore Different gaps in front or behind some vehicle types Plus: Gradients Widths Weather 16
From ideal capacity to Even in uninterrupted flow sections, some movements may reduce the ideal capacity, such as: Merging Diverging Weaving. 17
Capacity under interrupted conditions Traffic signals, roundabouts, all-stops Automobiles and trucks reaction times Saturation, blocking intersections (gridlock??) 18
0 Urban Transportation Planning Fall 2006 The Automobile Capacity Two-lane road Urban Roads Rural Roads Three signals Five signals per mile 12 8 4 0 Five or more signals per mile Less than five signals per mile Five or more signals per mile Thirty miles per hour Forty miles per hour 50-60 miles per hour Little nos Vs Fancy nos Four-lane road Two-lane road Four-lane road per mile { { One signal per mile Three signals per mile Expressways 60 miles per hour limit { Figure by MIT OCW. 400 800 1200 1600 2000 Vehicle volume, vehicles per hour per lane From Mayer and Miller 19 Travel time, minutes per mile
The Automobile Capacity PEOPLE throughput : Vehicle throughput times OCCUPANCY Auto-occupancy (a non-technical issue) HBW 1.1 HBO-shop 1.4 HBO-social 1.7 NHB 1.6 20
The Automobile Levels-Of-Service The power of A to F From spot values to travel times Living under saturated conditions www.bizkaimove.com 21
The Automobile Costs Fixed Costs: Vehicle purchase Insurance A parking spot/garage. Variables Costs: Gasoline Oil and maintenance Parking Tolls. Ratio between Fixed and Variable Costs? Why this is important? 22
The Automobile Costs Social costs: Road construction, maintenance Management of road system Environmental costs: Accidents Health impacts Noise (pedestrian areas) Air pollution: cold-start, f(speed) Land consumed Energy Segregation 24
Transit - Capacity People throughput: Vehicle size Headway (and fleet size) Commercial speed 26
Buses - Capacity Bus type and size: No of seated spaces and no of standees Access and ticketing: No of doors Easy access and egress Access by the front door, other doors Egress by one or two doors Low floor Ticket validation: By the bus driver On other machines on board On the bus stops 27
Buses - Capacity Capacity (Cont d): Headway: Peak-hour and off-peak Commercial speed: Mixed traffic Bus lanes Signal priority 28
Rail-based systems capacity Speed profiles between stations 113 70 97 60 Engine Governed Speed = 64 mph (103 km/h) 7.0 2.0 6.0 1.8 Speed (mph, km/h) 80 50 5.0 1.6 64 40 4.0 1.4 Speed-time 48 30 3.0 0.2 Distance-time 32 20 2.0 0. Cruise at Decelerate at 16 10 55 mph 2.5 mph/sec (88 km/h) (4 km/h/sec) 1.0 0. 0 10 20 30 40 50 Time (sec) 60 70 80 90 100 Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 29
Rail-based systems capacity Time-Space Diagrams Rate of change of slope represents acceleration Path of front of train Path of rear of train Distance Station platform = Train length Dwell time (sec.) Minimum safe separation Headway Constant slope represents balancing speed Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". Time 30
Transit LOS HBW represents > 50% Peak hours Peak directional flows Easy to accept overcrowding at peak to justify service during off-peak hours 31
Transit - LOS Originally, just density as for automobiles!! LOS BUS ft 2 /p p/seat* ft 2 /p RAIL p/seat* COMMENTS A B C >12.9 0.00-0.50 >19.9 0.00-0.50 8.6-12.9 0.51-0.75 14.0-19.9 0.51-0.75 6.5-8.5 0.76-1.00 10.2-13.9 0.76-1.00 No passenger need sit next to another Passengers can choose where to sit All passengers can sit D 5.4-6.4 1.01-1.25 5.4-10.1 1.01-2.00 Comfortable standee load for design E 4.3-5.3 1.26-1.50 3.2-5.3 2.01-3.00 Maximum schedule load F <4.3 >1.50 <3.2 >3.00 Crush loads *Approximate values for comparison LOS is based on area per passenger. Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 32
Transit - LOS PASSENGER POINT OF VIEW QUALITY OF SERVICE AVAILABILITY 1. Service coverage 2. Hours of service 3. Sidewalk condition 4. Park & Ride spacing CONVENIENCE 1. Passenger loading 2. Transit/auto travel time 3. Amenities 4. Safety Figure by MIT OCW. 33
Transit - LOS Category Service & Performance Measures Transit Stop Route Segment System Frequency* Hours of service* Service coverage Availability Accessibility Passenger loads Accessibility % person-minutes served Comfort and Convenience Passenger loads* Amenities Reliability* Travel speed Transit/auto travel time Travel time Reliability Transit/auto travel time Safety Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 34
Transit - LOS Different points of view to judge LOS: TRANSIT/AUTO TRAVEL TIME LOS LOS Travel Time Difference (min) Comments A B C D E F < _ 0 1-15 16-30 31-45 46-60 >60 Faster by transit than by automobile About as fast by transit as by automobile Tolerable for choice riders Round-trip at least an hour longer by transit Tedious for all riders; may be best possible in small cities Unacceptable to most riders Open to many interpretations: Times door-to-door? Weight factors applied to the different time segments? Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 35
Transit - Cost Capital Costs: >50-75 years horizon (infrastructure) Usually not included in fare-box recovery ratio for operating costs 12-40 years for vehicles (buses or trains) Operating Costs: C op =C d *veh-miles +C t *veh-hr + C s *fleet (with variations for peak and off-peak) Environmental Costs: Accident rate Noise, soot 36
Buses Flexibility for route adjustments Closer stop spacing In search of higher quality: Low floor buses for an aging population Bus stops: Real time info on arrivals (and eventually downstream) Maps, transfers, info on ticketing and validation 37
Viajeros anuales/310 10000 5000 2500 sube Metro 90,000 viajeros en 11 estaciones Rail vs Bus Viajeros 11/12/2000 suben 3000 1500 750 BilboBus 90,000 viajeros en >180 paradas 38
Light Rail From Rapid Rail Transit to Light Rail: Lower investments But more exciting than buses Mixed traffic segments Easier to garner support for priority Attracts local development 39
Light Rail Full reserved ROW or mixed traffic 40
Light Rail Priority easily awarded 41
From Public Transport to Collective Transport Urban Transportation Planning Fall 2006 Rethinking transit: Jitney service Taxi-Bus Dial-a-Ride Taxi Car Sharing.?? 42
Some comparative little numbers Car on city streets Car on Freeway Bus LRT on Mixed Traffic Semi Rapid Transit Rapid Transit Vehicle occupancy 1.2 1.2 40-300 40-600 140-2,200 Speed (km/hr) 20-50 60-120 5-20 15-45 25-70 Veh/hr 600-800 1500-2200 60-80 40-90 10-40 Capacity (pers/hr) 720 to 1,050 1,800 to 2,600 2,400 to 20,000 4,000 to 20,000 10,000 to 72,000 43
Walking See LOS C and E per HCM Capacity and LOS Moving and Waiting Is it enough?? Figure by MIT OCW. 45
Walking How to define LOS? What else should come into the picture? Comfort and safety Protection from weather Direct lines of sight Direct routing Live facades Conviviality??? The Tube Platforms 46
Biking L.O.S. The power of a can of paint Safety first and foremost 47
Biking- LOS Again, LOS based on throughput whether it is one-way or two-way Other concepts to be included in LOS? Inclines safety issues continuity drainage wet leaves..? 48
Biking: A process 49