Transport Modes and Technologies A Walking Tour on Capacity, LOS. Urban Transportation Planning MIT Course 1.252j/11.

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1 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

2 Transport Modes and Technologies Private Transport: The automobile Collective Transport Bus Light Rail Rapid Transit Taxi, CarSharing Non Motorized Modes Walking Biking 2

3 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

4 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

5 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

6 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

7 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

8 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

9 The Automobile Capacity Vehicle throughput in uninterrumpted flow: Speeddensity curves FFS = 120 km/h LOS A Density = 7 pc/km/ln B C D E 20 Note: FFS= Free-flow speed Flow Rate, v (pc/h/ln) p Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 13

10 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) 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) A Flow-Flow Speed (mph) > Flow Rate (pcphpl) B C D E Capacity (pcphpl) pcpmpl 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

11 Speed-Flow Curves Urban Transportation Planning Fall 2006 Unstable Flow Stable Flow Flows (Vehicles/hour/lane) Toll Range Undersaturated Oversaturated Shock Wave Density at Flow Capacity Flow at the bottleneck Density (Vehicles/km/lane) Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 15

12 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

13 From ideal capacity to Even in uninterrupted flow sections, some movements may reduce the ideal capacity, such as: Merging Diverging Weaving. 17

14 Capacity under interrupted conditions Traffic signals, roundabouts, all-stops Automobiles and trucks reaction times Saturation, blocking intersections (gridlock??) 18

15 0 Urban Transportation Planning Fall 2006 The Automobile Capacity Two-lane road Urban Roads Rural Roads Three signals Five signals per mile 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 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 Vehicle volume, vehicles per hour per lane From Mayer and Miller 19 Travel time, minutes per mile

16 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

17 The Automobile Levels-Of-Service The power of A to F From spot values to travel times Living under saturated conditions 21

18 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

19 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

20 Transit - Capacity People throughput: Vehicle size Headway (and fleet size) Commercial speed 26

21 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

22 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.

23 Rail-based systems capacity Speed profiles between stations Engine Governed Speed = 64 mph (103 km/h) Speed (mph, km/h) Speed-time Distance-time Cruise at Decelerate at mph 2.5 mph/sec (88 km/h) (4 km/h/sec) Time (sec) Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000". 29

24 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

25 Transit LOS HBW represents > 50% Peak hours Peak directional flows Easy to accept overcrowding at peak to justify service during off-peak hours 31

26 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 > > No passenger need sit next to another Passengers can choose where to sit All passengers can sit D Comfortable standee load for design E 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

27 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

28 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

29 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 < _ >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

30 Transit - Cost Capital Costs: >50-75 years horizon (infrastructure) Usually not included in fare-box recovery ratio for operating costs 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

31 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

32 Viajeros anuales/ sube Metro 90,000 viajeros en 11 estaciones Rail vs Bus Viajeros 11/12/2000 suben BilboBus 90,000 viajeros en >180 paradas 38

33 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

34 Light Rail Full reserved ROW or mixed traffic 40

35 Light Rail Priority easily awarded 41

36 From Public Transport to Collective Transport Urban Transportation Planning Fall 2006 Rethinking transit: Jitney service Taxi-Bus Dial-a-Ride Taxi Car Sharing.?? 42

37 Some comparative little numbers Car on city streets Car on Freeway Bus LRT on Mixed Traffic Semi Rapid Transit Rapid Transit Vehicle occupancy ,200 Speed (km/hr) Veh/hr 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

38 Walking See LOS C and E per HCM Capacity and LOS Moving and Waiting Is it enough?? Figure by MIT OCW. 45

39 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

40 Biking L.O.S. The power of a can of paint Safety first and foremost 47

41 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

42 Biking: A process 49

JCE 4600 Basic Freeway Segments

JCE 4600 Basic Freeway Segments HCM Applications What is a Freeway? divided highway with full control of access two or more lanes for the exclusive use of traffic in each direction no signalized or stop-controlled