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77 Cards in this Set
- Front
- Back
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lecture 1 learning goals
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eras in transportation
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-infrastructure era (before)
-systems era (now) -CLIOS era (future) |
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infrastructure era
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-build what "they" want
-focus on physical facilities -focus on mobility -focus on economic growth -largely a modal perspective |
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systems era
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-economics based framework: supply, demand, equilibrium, networks
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transportation as clios system
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Joe Sussman describes transportation as complex, large scale, interconnected, open, socio-economic system
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complex
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structural: the number of components in the system and the network of interconnections between them
-behavioral: the type of behavior that emerges due to the manner in which sets of components are connected |
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large scale
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geographic scope and impact
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interconnected
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connected with different systems (energy, technology, human, environment)
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open
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social, political, economic, equity factors
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socio-technical
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CLIOS ERA
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What are some of the common features of transportation modes (except walking)?
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21st Century Transportation Issues
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lecture 2 learning outcomes
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network
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-a set of nodes ,Ni, connected by a set of links, Lij
-A structure that serves and connects multiple nodes, people, flows and/or functions to achieve a goal. |
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directed v. undirected links
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directed: one way
undirected: two way -oriented network: all links directed -unoriented network: all links undirected -combo=mixed |
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point to point
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Point-to-point transit refers to a transportation system where a plane, bus or train travels directly to a destination, rather than going through a central hub
+It may minimize connections and travel time (only if the airline serves the destination via the origination point). With no need to satisfy connections, flights in a point-to-point system generally have no interdependency on other flights, apart from the operational constraints of the airline such as the number of aircraft and crew that are rostered to be in precise locations to satisfy the timetable. Overall, this therefore minimizes the risk of a "domino effect" whereby one delay can multiply into other delays elsewhere in the network, therefore a point-to-point system is less prone to delays. -If a city pair is not served, passengers are out of luck, as there is no way to get to a destination if they use that airline's route network. The frequency of flights may be reduced because a point-to-point system requires a large number of combinatoric |
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hub and spoke
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is a system of connections arranged like a chariot wheel, in which all traffic moves along spokes connected to the hub at the center.
+hub is very beneficial -Because the model is centralized, day-to-day operations may be relatively inflexible. Changes at the hub, or even in a single route, could have unexpected consequences throughout the network. It may be difficult or impossible to handle occasional periods of high demand between two spokes. |
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4 common types of transit networks
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-amorphous
-radial -grid -hub and spoke |
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amorphous networks
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-difficult to manage
-confusing for travelers -high degree of transfers and flexibility |
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radial networks
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-ideal for serving one central activity center
Difficult if central activity center changes (e.g old downtowns in the midwest) |
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grid network
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Ideal for wide area coverage
Increased likelihood of transfers. Multiple paths available to destinations |
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hub and spoke
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Good for multiple destination/activity areas
More economical Transfers can be challenging |
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L-matrix
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shows shortest distance between two nodes on the network
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r-matrix
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shows the exact path to be followed tog et from one node to another in the shortest distance
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flow theory
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Starting point to understand how traffic demand manifests itself on to the network
-People want to travel in the quickest/least expensive/most efficient way possible which is affected by: Human Behavior Physical Conditions/Infrastructure Technology Destinations Modes |
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is shortest distance path always the shortest time to travel?
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no, travel time not only depends ont he dstaince but also on volume and capacity
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speed
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Volumes or Flow Rate
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Density
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Number of vehicles occupying a given length of highway or lane (generally expressed as vehicles per mile)
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Bus
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A mode of transit service characterized by roadway vehicles powered by diesel, gasoline, battery, or alternative fuel engines contained within the vehicle.
Vehicles operate on streets and roadways in fixed-route or other regular service. Local bus service typically involves vehicles stopping every block or two along a route several miles long. |
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Light Rail
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Light Rail is a mode of transit service (also called streetcar, tramway, or trolley) operating passenger rail cars singly (or in short, usually two-car or three-car, trains) on fixed rails in right-of-way that is often separated from other traffic for part or much of the way.
Light rail vehicles are typically driven electrically with power being drawn from an overhead electric line via a trolley or a pantograph; driven by an operator on board the vehicle; and may have either high platform loading or low level boarding using steps. |
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Commuter Rail
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A mode of transit service (also called metropolitan rail, regional rail, or suburban rail)characterized
by an electric or diesel engine -Regional rail (also called metropolitan rail, commuter rail, or suburban rail) is an electric or diesel propelled railway for urban passenger train service consisting of local short distance travel operating between adjacent cities and towns, or between a central city and adjacent suburbs, using either locomotive hauled or multiple unit railroad passenger cars. |
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Heavy Rail
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-A heavy rail system is an electric railway with the capacity to handle a heavy volume of traffic.
-characterized by high speed and rapid acceleration passenger rail cars operating singly or in multi car trains on fixed rails |
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ight of Way
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Dedicated
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Transit users:
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◦ Captive users (also known as transit dependent riders) MUST take transit as they
do not have access to a private vehicle ◦ Choice users (also known as discretionary riders) have access to a private vehicle, but CHOOSE to use transit instead |
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Non-transit users:
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◦ Auto users (also known as Auto-Captive) MUST take their private auto as they do
not have (realistic) access to transit ◦ Potential users COULD take transit, but choose to take their private auto instead. |
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Affordability
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“extent to which the financial cost of journeys put an individual or household in the position of having to make sacrifices to travel or the extent to which they can afford to travel when they want to”
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Density
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People or jobs per unit of land area (acre or hectare).
-increased density reduces per capita vehicle travel |
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mix land use
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-People or jobs per unit of land area (acre or hectare).
-Increased land use mix tends to reduce per capita vehicle travel, and increases use of alternative modes, particularly walking for errands. Neighborhoods with good land use mix typically have 5-15% lower vehicle- miles. |
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regional accesibility
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-Increased land use mix tends to reduce per capita vehicle travel, and increases use of alternative modes, particularly walking for errands. Neighborhoods with good land use mix typically have 5-15% lower vehicle- miles.
-Improved accessibility reduces per capita vehicle mileage. Residents of more central neighborhoods typically drive 10-30% fewer vehicle-miles than residents of more dispersed, urban fringe locations. |
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centeredness
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-Improved accessibility reduces per capita vehicle mileage. Residents of more central neighborhoods typically drive 10-30% fewer vehicle-miles than residents of more dispersed, urban fringe locations.
-Improved accessibility reduces per capita vehicle mileage. Residents of more central neighborhoods typically drive 10-30% fewer vehicle-miles than residents of more dispersed, urban fringe locations. |
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connectivity
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-Improved accessibility reduces per capita vehicle mileage. Residents of more central neighborhoods typically drive 10-30% fewer vehicle-miles than residents of more dispersed, urban fringe locations.
-Improved roadway connectivity can reduce vehicle mileage, and improved walkway connectivity tends to increase walking and cycling. |
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Roadway design and management
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-Scale, design and management of streets.
-More multi-modal street design and management increases use of alternative modes. Traffic calming tends to reduce vehicle travel and increase walking and cycling. |
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Mobility Management
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Mobility management policies and programs can significantly reduce vehicle travel by affected trips. Vehicle travel reductions of 10-30% are common.
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Household composition
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Institutional Framework
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Four characteristics stand out
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From a Transport Side - Primary Challenges & Issues
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What is traffic congestion
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FHWA defines congestion as:
◦ “the level at which transportation system performance is no longer acceptable due to traffic interference." Related to 3 variables – speed, density, and flow Occurs when traffic density (veh/km) reaches saturation point Two different types: ◦ Recurring ( rush-hour) ◦ Non-recurring (accidents / road maintenance / new construction / special events / bad weather) Results in: ◦ Increased travel times / reduced speeds ◦ Increased travel time variability |
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congestion in spatial dimension
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Why does congestion occur?
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What can be done to reduce congestion?
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� Increase supply (highway capacity)
� Reduce demand � Manage existing demand more efficiently |
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Theory of Induced Demand
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How do we currently pay for road use?
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Examples of variable pricing
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Managed Lanes
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Road Tolling in the United States - Future
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Value Pricing / Express Lanes
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What is a HOT Lane?
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Public and Stakeholder Acceptability
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summary lecture 4
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� � Managed lanes utilize different lane management strategy combinations to enhance the efficiency and flexibility of traffic operations on existing roadway corridors Typically a freeway within a freeway Can be a Win-Win scenario if managed lanes are provided as additional to general purpose lanes Public acceptability can be high if managed lanes are perceived as a choice Legislation, political will and technical expertise are required to make it feasible |
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18th C - Sail era
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Focused on Atlantic and Coastal Trade. At the time of the American Revolution, it cost as much to move a ton of goods 30 miles inland as to move it across the Atlantic.2 Two out of three settlers lived within 50 miles of the Atlantic coast.
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Rail Era- (19th C)
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Focused on East–West Corridors and Key Hubs East–west rail routes were built to follow development of the Midwest, and after the Civil War, to solidify political and military control of the West. But north–south rail routes were slow to develop because the railroads could not compete effectively with water transport for coastal trade
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Truck Era- (20th C)
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An east–west and north–south interstate highway grid was built to connect cities and regional economies. Long-haul trucking captured a large share of east–west freight traffic from railroads and much of the north–south freight traffic from coastal steamers and river barges.
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Integration and Information Era(21st C)
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Causes for freight delays
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lecture 5 recap
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◦ A wireless communications channel used for broadcast and interactive close-proximity communications between vehicles and the immediate infrastructure.
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fixed point-fixed point communications
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◦ A communications link that provides communications among
stationary entities. � Applications ◦ Traffic Signal Control ◦ Network Surveillance ◦ System Monitoring |
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Vehicle - Vehicle Communications
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◦ A short range wireless communications link among vehicles
(e.g. mobile system to mobile systems). -applications Advanced collision avoidance implementations, ◦ Road condition information sharing, ◦ Active coordination between advanced vehicle control systems. |
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Wide Area Wireless (Mobile) Communications
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◦ A wireless communications system that offers broad coverage, enabling communications with vehicles and traveler mobile devices at any location on or off the road network. Both broadcast (one-way) and interactive (two-way)
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active traffic management
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Definition: the ability to dynamically manage recurrent and non-recurrent congestion based on prevailing traffic conditions. Focusing on trip reliability, it maximizes the effectiveness and efficiency of the facility and increases throughput and safety. This approach consists of a combination of operational strategies, that when implemented in concert, fully optimize the existing infrastructure and provide measurable benefits to the transportation network and motoring public.
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speed harmonization
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Definition: the ability to dynamically manage recurrent and non-recurrent congestion based on prevailing traffic conditions. Focusing on trip reliability, it maximizes the effectiveness and efficiency of the facility and increases throughput and safety. This approach consists of a combination of operational strategies, that when implemented in concert, fully optimize the existing infrastructure and provide measurable benefits to the transportation network and motoring public.
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que warning
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Inform motorists of reason for slower speeds
Includes congestion, accident and construction Integrated into overhead system |
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dynamic merge control
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Gives priority to lane with higher volume
Can prevent conflicts at merge and downstream queuing |
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Putting It All Together – M42 UK
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• Use of hard shoulder
• Break-down areas • Driver info panels • Speed control • Photo enforcement • CCTV |
