Grid Un-Locked - Week 3

Kimley-Horn and Associates, Inc.

SARASOTA TRANSPORTATION 101
WEEK 3
OCTOBER 10, 2017
CHRISTOPHER HATTON, P.E.
Traffic Impact Studies
and Our Multi-Modal Future

Presentation Overview:
Transportation 101
Transportation Impact Studies
> Advantage or Disadvantage!?
> County and City Requirements
> A TIS…Step-By-Step
Multi-Modal Mobility Fee
> Old – Concurrency and Transportation Impact Fees
> New – Mobility Fee and ???
What’s Next?

Transportation Impact Studies:
Advantage or Disadvantage?
Advantage!
Help to accurately identify traffic impacts from
development
Help overloaded County staff
Help identify needed transportation improvements for
Capital Improvement Program
Need to educate the public, and governing boards
(Planning Commissions, BOCC, etc)

Advantage or Disadvantage?
Disadvanatge?
“Old Days” (with concurrency, pre-2011) rules would
push out development to the suburbs
Note: “New Rules” (with mobility fees, current)
encourages urban and in-fill development
Don’t have to build the improvement, now “Pay and Go”
County and City still have some type of transportation
study requirements

County and City
Sarasota County and City of Sarasota
County
Even with the Adoption of the Mobility Fee in 2016,
the County still requires a traffic study (Operational
Analysis, and “Still To Be Decided”)
City
Has (three) Traffic Consultants that conduct specific
traffic studies for development proposed in the City

TRAFFIC IMPACT STUDIES
“Site transportation impact studies should be prepared
under the supervision of a qualified and experienced
transportation professional who has specific training in
traffic and transportation engineering and planning and
several years of experience related to preparing
transportation studies for existing or proposed developments.
The ability to forecast and analyze transportation needs
both for developments and for transportation systems is
essential.”
Transportation Impact Analyses for Site Development,
Institute of Transportation Engineers, 2010.

PROJECT TRAFFIC
Trip: Journey from an origin to a destination
Trip End: The portion of a trip associated with either
the origin or the destination

Project Traffic
• Trip Generation
• Trip Distribution
• Mode Choice
• Assignments

TRIP GENERATION
Data Sources
▪ ITE Trip Generation
▪ Local standards
▪ New data

TRIP GENERATION
Pass-by capture
▪ Magnitude
▪ ITE Trip Generation Handbook
▪ Adjacent street traffic (10% or 15% of total)
▪ Local criteria and other limitations
▪ Enter / Exit based on land use

Project Site
Street
Avenue Oi Di
Internal
On
Dn
Pass-by
Op
Dp
New
PB

TRIP GENERATION
Summary:
Driveway Volume calculated for each use
- Internal Capture
= External Trips (project driveway volumes)
- Pass-by Capture
= New External Trips

TRIP DISTRIBUTION
▪ Origins and destinations
▪ Productions and attractions

Project Site
Avenue
400 vph
600 vph
Project Site
Oeb Deb
60%
Dwb Owb
40%

TRIP DISTRIBUTION
Travel demand forecast model
▪ Gravity model
▪ Travel times
▪ Balance Productions and
Attractions

MODE CHOICE
Modes
▪ Passenger cars (single and multiple occupancy)
▪ Bus
▪ Rail
▪ Bicycle
▪ Walking
▪ Truck
▪ Taxi

MODE CHOICE
Effective range and typical usage
Mode Range Suburban
Usage
Urban Usage
Automobile No limit 90% to 100% 75% to 95%
Transit (all types) Defined routes < 5% 5% to 25%+
Bicycle 5 miles <1% <2%
Walking ½ mile <1% <2%
Truck (freight) No limit <1% <1%

ASSIGNMENTS
What to assign
▪ Mode
▪ Trip type
▪ Internal capture
▪ Pass-by capture
▪ Diverted link
▪ New

ASSIGNMENTS
New Trips: Travel demand forecast model
▪ Total volumes
▪ Isolating project traffic
▪ Select zone
▪ Select link
▪ Comparative total volume runs (With & Without)

Analysis Scenarios
Study Area
Existing Volumes
Future Non-project
Total Future
Conditions
Site Access
Crashes
Recommendations

ANALYSIS SCENARIOS
Volumes
▪ Existing
▪ Future years
▪ Non-Project (a/k/a Background or Non-site)
▪ Total, includes project traffic
▪ Level of detail may vary by phase:
“Detailed analyses (such as turning movements) should not be required for
horizon dates beyond 10 years in the future. There are far too many
variables that can change over time and preclude the development of
accurate traffic forecasts.”
Transportation Impact Analyses for Site Development,
Institute of Transportation Engineers, 2010.

STUDY AREA
Study to be submitted to agencies
▪ Jurisdictional requirements
▪ Legislative
▪ Guidelines
▪ Negotiated

STUDY AREA
Transportation Impact Analyses for Site Development
Summary of Suggested Study Area Limits
Development Peak Hour
Trips
Study Area
Small commercial sites < 200 Adjacent intersection and roads
Small shopping centers 200 to 500 Signals and roads within ½ mile
and major unsignalized
intersections within ¼ mile
Medium shopping centers
and offices, medium to large
mixed use developments
>500 All roads and major
intersections within 1 mile
Larges shopping centers,
office, other developments
>500 All roads and major
intersections within 2 miles

EXISTING VOLUMES
Usability of traffic volume counts
▪ Public agencies
▪ Most recently published
▪ No more than two years old
▪ Kimley-Horn or other consultants
▪ Within prior 12 months
▪ If older than 12 months, calibrated

EXISTING VOLUMES
▪ Annual average
▪ Design hour
▪ Peak season
▪ Special event

FUTURE NON-PROJECT
Methods
▪ Historical growth rates
▪ Traffic from other projects
▪ Model derived growth rates
▪ Model generated volumes
▪ Combinations

FUTURE NON-PROJECT
Funded road improvements
▪ Construction funding
▪ Committed by
▪ public agency
▪ other entity with security issued

FUTURE NON-PROJECT
New roads
▪ Manual Calculations
▪ Diversion from existing facilities
▪ Latent demand
▪ Travel Demand Model
When a road is once built, it is a
strange thing how it collects traffic.
-Robert Louis Stevenson

TOTAL FUTURE CONDITIONS
▪ Volumes
Non-Project + Project = Total
▪ Roadway network
▪ Base
Existing + Committed for construction (E+C)
▪ Improvements
E+C plus recommended improvements

SITE ACCESS
Factors to be balanced
▪ Access management standards
▪ Site constraints
▪ Traffic operations on road network
▪ Traffic circulation within the site

SITE ACCESS
Access management principles
▪ Manage roadways according to the primary functions that they serve
▪ Limit direct access to major roadways
▪ Promote intersection hierarchy
▪ Locate signals to favor through movements
▪ Don’t allow driveways to interfere with intersection or interchange
operations
▪ Limit the number of conflict points
▪ Separate conflict points
▪ Remove turning vehicles from through traffic lanes
▪ Manage left-turn movements using medians
▪ Provide a complete, supporting street system

SITE ACCESS
Access management standards
▪ Corner Clearance
▪ Driveway spacing
▪ Median opening spacing
▪ Traffic signal spacing
▪ Interchange spacing
▪ Interchange ramp treatments

State of Florida Access Management Standards

SITE ACCESS
Traffic circulation within the site
▪ Queuing – entering and exiting
▪ Parking
▪ Pedestrians
▪ Fire lanes and emergency access
▪ Transit (large sites)
▪ Heavy vehicles
▪ Public facilities through site

SITE ACCESS
Traffic circulation within the site: Queuing
▪ Signalized intersections
▪ Analysis outputs
▪ Manual: Storage length = 2 x PHV/ cycles per hour
▪ Unsignalized intersections
▪ Manual: Storage length = PHV/ 30
▪ Minimums
▪ Left-turns: 100 feet
▪ Right-turns: 25 feet
▪ Right-turn needs may be reduced using g/c ratio

CRASHES
▪ Agency data
▪ Crash reports from law enforcement agencies
▪ Summary reports, typically from State DOT
▪ Preparing diagrams
▪ Purpose
▪ Standard conventions

RECOMMENDATIONS
Options
▪ Site plan alterations
▪ Access locations, size, and type
▪ Internal circulation
▪ Intersections
▪ Signal phasing and timing
▪ Geometric improvements
▪ Roadways
▪ Access management
▪ Additional lanes
▪ New roads

Multi-Modal Mobility Fee:
Old and New
Old Way…and Today
Old: Transportation Concurrency and Impact Fees
Concurrency study determined what improvements
were required of the developer
PLUS…Transportation Impact Fees
Today: Mobility Fees and ???
Sarasota County adopted January 1, 2016 a Mobility
Fee for the entire County
Is now determining what else to require!?

Multi-Modal Mobility Fee:
Old and New

Traffic Studies in Sarasota:
What is Next?
Mobility Fee Payments based upon Land Use
Mobility Fee payments currently being used for
improvements ($900,000 on Legacy Trail)
Operations Analysis and ???
Sarasota County developing Multi-Modal Traffic
Study Methodology
Meeting with County staff in November 2017

TRAFFIC
CONGESTION
CAR PARKING

CONVENIENCE & WALK DISTANCE
City of Denver User Group Study,
Strategic Parking Plan April 2010

Upper West Manhattan
2008 Study Aggregate
3.1 Minutes & .37 miles
1 year = 366k miles &
325 tons of CO2
Traffic Studies
Question:
If cruising is reduced,
where would cars go?

DRIVERS WOULD SPEND LESS TIME DRIVING,
MAKE SHORTER TRIPS, USE LESS GAS (CO2).

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