Transportation Engineering Contents History of transportation Current U.S. state of transportation Careers in transportation Transportation education curriculum The future of transportation History of Transportation The first pipeline in the US was introduced in 1825
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History of transportation
Current U.S. state of transportation
Careers in transportation
Transportation education curriculum
The future of transportation
The first pipeline in the US was introduced in 1825
First railroad opened in 1825
The internal combustion engine was invented in 1866
The first automobile was produced in 1886 (by Daimler and Benz)
The Wright brothers flew the first heavier-than-air machine in 1903
The first diesel electric locomotive was introduced in 1921
Lindbergh flew over the Atlantic Ocean to Europe in 1927
The first diesel engine buses were used in 1938
The first limited-access highway in the US (the Pennsylvania Turnpike) opened in 1940
The interstate highway system was initiated in 1950
The first commercial jet appeared in 1958
Commercial air transportation began in 1914 when the St. Petersburg-Tampa Air Boat Line briefly carried the first scheduled paying passengers across Tampa Bay, Florida
After 1926, the airlines were created to carry first the air mail and later passengers in regular service.
By World War II, the United States had a well-developed modern network of air routes and airlines linking every state and reaching across the oceans.
From Douglas M-2 in 1920s
To Being 777 in 2000s
General Motors offered air bags in the 1973 model Chevrolet as an option. By 1988, Chrysler became the first company to offer air bag restraint systems as standard equipment. In 1994, TRW began production of the first gas-inflated air bag.
The first car with an actual cooling system was the 1940 model year Packard. In 1953 General Motors, Chrysler and Packard each introduced an air conditioning system.
In 1901, British inventor Frederick William Lanchester patented disc brakes.
In 1929, American Paul Galvin, the head of Galvin Manufacturing Corporation, invented the first car radio.
Cruise control was first offered in the 1958 Chrysler Imperial, New Yorker and Windsor car models.
In 1854, Samuel McKeen of Nova Scotia designed the first version of the odometer, a device that measures mileage driven.
In 1904, a car called the Christie featured a tire on a mountable rim. The tire and rim could be removed to allow the motorist to repair a flat along the roadside.
Power steering became commercially available by 1951.
Buick introduced the first electric turn signals in 1938.
Volvo had the first safety belts in 1849.
Mary Anderson invented the windshield wiper. Anderson was issued a patent for the wipers in 1905. The wipers were standard equipment on all American cars by 1916.
A look at transportation statistics
A look at crash statistics
What transportation engineers do
Geometric design of highways
Highway/intersection capacity studies
Highway safety studies
Traffic control devices
Traffic flow characteristics
Urban transportation planning
Access management / Traffic calming
What are the four elements interacting on the roadway?
(i) Road user (or the human element)
(iv) Traffic control device
Definition of the road users
The road users are defined as drivers, passengers, bicyclists, and pedestrians who use streets and highways
What are road user characteristics?
(i) Senses: the driver can receive useful information regarding the safe control of the vehicle through feeling, seeing, hearing, and smelling.
(ii) Mind and nerves: by which the driver learns, decides, and connects his/her senses with the muscles. These are intelligence, judgement of space and motion, and coordination of bodily movements.
(iii) Bones and muscles: by which the driver directs and controls his/her vehicle and moves his/her body. These are the stature to fit vehicle and its controls, limbs to connect with and operate regular and special controls, and body movements.
Seeing or (visual perception)
The principle characteristics of the eye are visual acuity, peripheral vision, color vision, glare vision and recovery, and depth perception.
Visual acuity is the ability to see fine details clearly. The most acute vision is within a narrow cone of 30-50, fairly clear sight within 100-120.
Peripheral vision is the ability of a driver to see objects beyond the cone of clearest vision.
Color blindness is the reduced ability to distinguish between red and green. It is estimated that 8% of all men and 4% of all women suffer some degree of color blindness.
Glare vision and recovery is important in designing and locating street lighting, median barriers, tunnel lights.
Perception-and-reaction process (PIEV theory)
The driving task is a continuous series of sensory cues that the motorist must monitor and respond to. The perception of, and reaction to, a particular cue or stimulus involves four distinct actions on the part of the driver:
i. Perception: The recognition or realization that a cue or stimulus exists that requires a response
ii. Intellection or identification: The identification or interpretation of the cue or stimulus
iii.Emotion or decision: The determination of an appropriate response to the cue or stimulus
iv. Volition or reaction: The physical response that results from the decision
Consider a typical example of a driver approaching a STOP sign. The driver first sees the sign (perception), then recognizes it as a STOP sign (intellection), then decides to STOP (emotion), and finally puts his or her foot on the brake (volition).
Why is perception-reaction time important in design?
(i) Used to determine safe stopping distance
(ii) Used to determine minimum sight distance
(iii) Used to determine the length of the yellow phase at a signalized intersection
See Figure 3-2 (McShane&Roess) for 85th-percentile perception-reaction time
AASHTO recommends a perception-reaction time of 2.5 seconds for design
What is the Distance Traveled During Perception-Reaction Time?
Distance (d) = Speed (v) x time (t)
d in feet, v in ft/sec, and t in seconds
Example: Given: t=2.5 seconds and v=55 mph
Solution: d = v . T = 55 x 1.47 x 2.5 = 202 ft.
What are important vehicular characteristics considered in design?
viii. Tire friction
See table for details
Type of trucks on highways
Minimum turning path
What are the four basic elements of geometric design?
a. Horizontal alignment
b. Vertical alignment
c. Cross-section design
Horizontal and vertical alignment are controlled by two basic design criteria:
a. Design speed
b. Sight distance
Design speed is defined as the maximum safe speed that can be maintained over a specified section of a highway when conditions are so favorable that the design features of the highway govern.
There are two types of sight distance used in designing highways:
a. Stopping sight distance
b. Passing sight distance
Stopping sight distance
Stopping sight distance is the distance required to see an object 6 inches high on the roadway. It is intended to allow drivers to stop safely after sighting an object on the roadway large enough to cause damage to the vehicle or loss of control
Passing sight distance
Passing sight distance is the distance required to see an oncoming vehicle of a certain minimum size. A passing driver must have sight distance to observe an oncoming vehicle at a distance sufficient to allow him or her to enter the opposing lane, pass a moving vehicle, and return to the travel lane safely. See Figure 3.2 (Banks) for illustration of passing distance.
Highway geometric design and visualization tools
Importance of signals
Signal timing fundamentals
Example of traffic calming
Intelligent Transportation Systems
A signal cycle is one complete rotation through all of the indications provided
The cycle length is the time (in seconds) that it takes a signal to complete one full cycle of indications. See Figure 8.7.
A phase is that part of a cycle allocated to a stream of traffic, or a a combination of two or more streams of traffic, having the right of way simultaneously during one or more intervals. See Figure 11.1.
An interval is any part of the cycle length during which signal indications do not change.
The change interval is the total length of time in seconds of the yellow and all-red signal indications. This time is provided for vehicles to clear the intersection after the green interval. See Figure 8.6.
A “permitted” left turn is made across an opposing through vehicle flow. In such cases, the driver is “permitted” to cross the opposing though flow, but must select an appropriate gap in the opposing stream through which to turn.
A “protected” left turn is made without an opposing through vehicular flow. The signal phasing “protects” left-turning vehicles by prohibiting the opposing through movement.
Protected/Permitted or Permitted/Protected Left Turns: More complicated signal phasing can be designed in which left turns (on a given approach or approaches) have a protected turn for part of the cycle and a permitted turn for another part of the cycle.
The peak-hour factor (PHF) is a measure of the variability of demand during the peak hour and is given by:
The design hourly volume (DHV) is therefore given by:
DHV = Peak-hour volume / PHF. See Example 8.3
The passenger car equivalent (PCE) is a factor used to convert straight-through volume of buses and trucks to straight-through volumes of passenger cars.
Turning movement factors are required because turning vehicles generally require a longer green time than straight-through vehicles.
2. What is the objective of Signal Timing?
The main objectives of signal timing at an intersection are to reduce the average delay of all vehicles and the probability of accidents. These objectives are achieved by minimizing the possible conflict points when assigning the right of way to different traffic streams at different times. See Figure 8.3.
The main purpose of the yellow indication after the green is to alert drivers to the fact that the green light is about to change to red and to allow vehicles already in the intersection to cross.
(1) Advanced Traffic Management Systems (ATMS)
(2) Advanced Traveler Information Systems (ATIS)
(3) Advanced Vehicle Control Systems (AVCS)
(4) Commercial Vehicle Operations (CVO)
(5) Advanced Public Transportation Systems (APTS)
(6) Advanced Rural Transportation Systems (ARTS)
The objective of ATMS is to monitor, control, and manage traffic on freeways, arterials, corridors, etc. through:
emergency, fire crews, etc.
The objective of CVO is to expedite and improve commodity movement through:
4. Barriers and Challenges for ITS