HGD501_Lecture 1 Transportation Planning_16d81dc44b28dc1872ff5cf10849a25b.pdf

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1. Glpa Ali Mahmood, M.Sc.
Civil Engineering/Highway Engineering
Email: [email protected]
9/9/2024HGD501: Highway Geometric Design and Planning
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HGD501 Highway Geometric Design and Planning

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Lecture 1: The Transportation Planning Process
HGD501: Highway Geometric Design and Planning

3. The Transportation Planning Process
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Thislectureexplainshowdecisionstobuildtransportation
facilitiesaremadeandhighlightsthemajorelementsofthe
process.
TransportationPlanninghasbecomeinstitutionalized;federal
guidelines,regulations,andrequirementsforlocalplanningare
oftendrivingforcesbehindexistingplanningmethods.
Theformationofthenation’stransportationsystemhasbeen
evolutionary,nottheresultofagrandplan.
Thesystemnowinplaceistheproductofmanyindividual
decisionstoselectprojectsforconstructionorimprovement,such
asbridges,highways,tunnels,harbors,railwaystations,and
airportrunways.
HGD501: Highway Geometric Design and Planning

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Amongthefactorsthatmayjustifyatransportationprojectare:
▪Trafficflowandsafety.
▪Energyconsumption.
▪Traveltime.
▪Economicgrowth.
▪Andaccessibility.
Some transportation projects may have been selected for reasons
unrelated to specific benefits, for example:
▪To stimulate employment in a particular region.
▪To compete with other cities or states for prestige.
▪To attract industry.
▪To respond to pressures from a political constituency.
▪Or to gain personal benefit from a particular route location or
construction project.
In some instances, transportation projects are not selected because
of opposition from those who would be adversely affected.
HGD501: Highway Geometric Design and Planning

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The process for planning transportation systems should be:
▪Arationalonethatservestofurnishunbiasedinformationaboutthe
effectsthattheproposedtransportationprojectwillhaveonthe
affectedcommunityandonusers.
▪Theprocessmustbeflexibleenoughtobeapplicabletoany
transportationprojectsystem,becausethekindsofproblemsthat
transportationengineersworkonwillvaryovertime.
▪Thetransportationplanningprocessisnotintendedtofurnisha
decisionortogiveasingleresultthatmustbefollowed,althoughit
candosoinrelativelysimplesituation.
▪Rather,theprocessisintendedtoprovidetheappropriate
informationtothosewhowillbeaffectedandthoseresponsiblefor
decidingwhetherthetransportationprojectshouldgoforward.
HGD501: Highway Geometric Design and Planning

6. Basic Elements of Transportation Planning
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The Transportation planning process comprises seven basic
elements:
▪Situation definition (existing travel and facilities)
▪Problem definition (goals and objectives)
▪Search for solutions (alternatives)
▪Performance analysis (performance measures)
▪Evaluation of alternatives(cost-benefit ratio)
▪Choice of project (best alternative)
HGD501: Highway Geometric Design and Planning

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SituationDefinition:
▪Whichinvolvesalloftheactivitiesrequiredtounderstandthe
situationthatgaverisetotheperceivedneedforatransportation
improvement.
▪Inthisphase,thebasicfactorsthatcreatedthepresentsituation
aredescribed,andthescopeofthesystemtobestudiedis
delineated.
ProblemDefinition:
▪Thepurposeofthisstepis
todescribetheproblemintermsoftheobjectivestobeaccomplishedbythe
project,
Objectivesarestatementsofpurpose,suchastoreducetrafficcongestion;to
improvesafety;tomaximizenethighway-userbenefits;andto
reducenoise.
andtotranslatethoseobjectivesintocriteriathatcanbequantified.
Criteriaarethemeasuresofeffectivenessthatcanbeusedtoquantifythe
extenttowhichaproposedtransportationprojectwillachievethestated
objectives.
Forexample,theobjective“toreducetrafficcongestion”might
use“traveltime”asthemeasureofeffectiveness(MOEs).
HGD501: Highway Geometric Design and Planning

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SearchforSolutions:
▪Transportationengineerhasavarietyofoptionsavailableinanyparticular
situation.
▪Thisphasealsoincludespreliminaryfeasibilitystudies,whichmight
narrowtherangeofchoicestothosethatappearmostpromising.
▪Somedatagathering,fieldtesting,andcostestimatingmaybenecessaryat
thisstagetodeterminethepracticalityandfinancialfeasibilityofthe
alternativesbeingproposed.
AnalysisofPerformance:
▪Thepurposeofperformanceanalysisistoestimatehoweachoftheproposed
alternativeswouldperformunderpresentandfutureconditions.
▪Otherinformationabouttheuseofthesystem(suchastriplength,travelby
timeofday,andvehicleoccupancy)arealsodeterminedandusedincalculating
userbenefitsforvariouscriteriaormeasuresofeffectiveness.
▪Environmentaleffectsofthetransportationproject(suchasnoiseandair
pollutionlevelsandacresoflandrequired)areestimated.
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EvaluationofAlternatives:
▪Thepurposeoftheevaluationphaseistodeterminehowwelleachalternativewill
achievetheobjectivesoftheprojectasdefinedbythecriteria.
▪Theperformancedataproducedintheanalysisphaseareusedtocomputethe
benefitsandcoststhatwillresultiftheprojectisselected.
▪Forthoseeffectsthatcanbedescribedinmonetaryterms,thebenefit–costratiofor
eachprojectiscalculatedtoshowtheextenttowhichtheprojectwouldbeasound
investment.
ChoiceofProject:Projectselectionismadeafterconsideringallthefactors
involved.Inasimplesituation,forexample,wheretheprojecthasbeenauthorized
andisinthedesignphase,asinglecriterion(suchascost)mightbeusedand
thechosenprojectwouldbetheonewiththelowestcost.
SpecificationandConstruction:
▪Oncethetransportationprojecthasbeenselected,theprojectmovesintoadetailed
designphaseinwhicheachofthecomponentsofthefacilityisspecified.
▪Foratransportationfacility,thisinvolvesitsphysicallocation,geometricdimensions,
andstructuralconfiguration.
▪Designplansareproducedthatcanbeusedbycontractorstoestimatethecostof
buildingtheproject.
▪Whenaconstructionfirmisselected,theseplanswillbethebasisonwhichthe
projectwillbebuilt.
HGD501: Highway Geometric Design and Planning

10. 7 Basic Steps of Highway Planning (road performance improvement)
Situation Definition 1.Inventory transportation facilities
2.Measure travel patterns
Problem Definition Define objectives
1.Reduce travel time
Establish criteria
1.Average delay time
Define constraints
Search for Solutions 1.Maintain the existing road
2.Increase capacity by adding new lanes
3.Build a new road
Analysis of PerformanceFor each alternative
1.Determine cost
2.Determine traffic flow
3.Estimate impact on environment
Evaluation of Alternatives1.Compute benefits and costs
2.Rank alternatives accordingly
Choice of Project 1.Select the best alternative
Specification &
Construction
1.Conduct design (design standards)
2.Develop construction plans
3.Select contractor
4.Deliver completed project to authority for operation and
maintenance
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11. Example
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Planning improvement or possible relocation of a Rural Road
▪Traffic analysis
▪Environmental assessment

12. 7 Steps
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1: Situation definition
▪Relocation or reconstruction of 3.3 miles of U.S. 1A
▪The town Harrington, Maine is located near the intersection of highways
U.S. 1 and U.S. 1A on the banks of the Harrington river
▪The town has 553 residents (of whom 420 live in the study area and 350 live
in the town center)
▪The population has been declining in recent years; many young people have
left because of the lack of employment opportunities.
▪The town's industry consists of agriculture and fishing (any environmental
damage impacts people livelihood)
▪10 business establishment exist within the study area
▪Average daily traffic is 2620 veh/day
69 % is through traffic
31 % is local traffic
HGD501: Highway Geometric Design and Planning

13. 7 Steps
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2: Problem definition
▪Maine DOT intends to improveU.S. 1A primarily to reduce the high
accident rate on this road in the vicinity of the town center
▪The problem is caused by a narrow bridge on U.S. 1A into the town center
▪The poor horizontal and vertical alignment and the dangerous intersection
where U.S. 1A and U.S. 1 meet
▪The accident rate on U.S. 1A is four times the statewide average
▪The secondary purpose of relocation is to improve the LOS for through
traffic (69%) by increasing the average speed on the relocated highway
Criteria (measure of effectiveness)
▪Accident rate
▪Travel time (speed)
▪Construction cost
▪Others (business and home displacement, noise levels, air quality, and
environmental impact)
HGD501: Highway Geometric Design and Planning

14. 7 Steps
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3: Search for solutions (4 alternatives)
▪Alternative 0: do nothing
▪Alternative 1: bypasses the town to the south across Harrington river
Two lanes, 12 ftwide with 8 ftshoulders
A new bridge would be constructed

15. 7 Steps
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3: Search for solutions (4 alternatives)
▪Alternative 2: improvements to the horizontal and vertical alignment
and construction of a new bridge
▪Alternative 3: the new road would merge with U.S. 1 west of
Harrington and continue through the town
▪Alternative 4: the new road would merge with U.S. 1 and use the
existing bridge and bypass the town center

16. 7 Steps
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4: Analysis of performance
▪Existing accident factor is 4 times the statewide, would be reduced to
0.6 for alternative 4 and 1.2 for alternative 1. (primary purpose)
▪Average speed on the existing road is 25 mi/h while alternatives 1
and 4, speed is 55 mi/h, and for alternative 2 and 3, speed is 30
mi/h. (secondary purpose)
▪The project cost ranges from $1.18 million for alternative 3 to $1.58
million for alternative 2.
▪Other items calculated include number of residence displace, traffic
volume in town, air quality, noise, and trees removed.
HGD501: Highway Geometric Design and Planning

17. 7 Steps
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4: Analysis of performance
HGD501: Highway Geometric Design and Planning

18. 7 Steps
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4: Analysis of performance
HGD501: Highway Geometric Design and Planning

19. 7 Steps
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5: Evaluation of alternatives
▪Accident factor: best reduction with alternative 4
▪Travel time: best is alternative 1
▪Cost: the least costly is alternative 1, but the dramatic improvement in travel
time and safety would probably lead to construction of proposed project
Alternative 3 has lowest cost
Alternative 2 has highest cost, but not as safe as alternative 3
Alternative 1 would cost more than alternative 3
Alternative 4 would cost more than alternative 1
Therefore, alternatives 1 and 4 would be more attractive than alternatives 2
and 3
▪Residences:
3 would be displaced under alternative 3
7 under alternative 2
No impact on alternatives 1 and 4
HGD501: Highway Geometric Design and Planning

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Primary Purpose
Secondary Purpose
HGD501: Highway Geometric Design and Planning

21. 7 Steps
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5: Evaluation of alternatives
▪Air quality: alternative 1 would have the highest air quality
▪Noise: alternative 1 and 4 would have lower noise levels
▪Trees removed: alternative 1 with slight loss and alternative 2 with no
loss
6: Choice of project
▪From cost perspective, alternative 3 would be the best
Safety and travel time improvement with lowest cost
▪Alternative 1 is lower in cost than alternative 4 and better than
alternative 3 on each criterion (alternative 1 is chosen)
HGD501: Highway Geometric Design and Planning

22. 7 Steps
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7: Specifications and construction
▪Alternative 1 is chosen
▪Prepare design of the road and bridge
▪Announce bidding (award the company with lowest bid)
▪After completion, turn the road over to MDOT for operation and
maintenance
HGD501: Highway Geometric Design and Planning