PEDESTRIAN ACCOMMODATIONS DPS 201 AT INTERCHANGES
UNDERSTANDING THE ISSUES Intersections of freeway ramp terminals at crossroads are the most critical components of an interchange Challenge: balance mobility and safety of peds & bicycles with movement of vehicles Photo Source: Mark Doctor, FHWA I-40 at Carlisle Blvd Albuquerque NM
UNDERSTANDING THE ISSUES Free-flow ramp movements can be very challenging for pedestrians to cross I-55 exit to Main Street - Madison, MS Photo Source: Mark Doctor, FHWA
UNDERSTANDING THE ISSUES Drivers do not expect pedestrians around interchanges There is safety in numbers; but pedestrian numbers are usually low around interchanges After coming off freeway 45 mph appears to be a slow speed Provide visual cues Discontinuous facilities Free-flowing entry and exit ramps Insufficient lighting Unmarked crossings Poor sight distance Long crossing distances
RESOURCES
LACK OF NATIONAL GUIDELINES AASHTO - A Policy on Geometric Design of Highways and Streets 2011 6 th Edition 10 Grade Separations and Interchanges 10.1 Introduction and general Types of Interchanges To reduce conflicts between vehicles, pedestrians, or bicycles within interchanges, it is preferable to separate their movements. When separation of pedestrians and bicycle movements from vehicle traffic is not practical, each interchange site should be studied and alternate designs considered to determine the most appropriate arrangement of structures and ramps to accommodate bicycle and pedestrian traffic through and interchange area. 10.9 Interchanges The accommodation of pedestrian and bicyclists also should be considered in the selection of an interchange configuration
INTERCHANGES/LARGE INTERSECTIONS
PUBLISHED GUIDANCE
BEST PRACTICES Design for direct connections Mark crosswalks where ramps intersect local roads Use STOP signs or signals for pedestrian crossings Use appropriate warning signs Do not over-sign Provide adequate lighting Eliminate free-flow right turns where possible Ramp terminals should intersect local roads at right angles Right-turn slip lanes should use tighter angles Use only single rightturn lanes Accommodate bicycles
GUIDING PRINCIPLES Provide pedestrian & bicycle facilities Sidewalks Pavement markings Signing ADA accommodations Lighting Bike lanes Keep crosswalks short as possible but balance with most direct route Design ramp geometries to encourage slower vehicle speeds Provide good visibility
PEDESTRIAN & BICYCLE ACCOMMODATIONS Just do it!
PEDESTRIAN ACCOMMODATIONS Apply Principles from DPS 101 & DPS 201 Sidewalks or shoulders Zone System when designing sidewalks Crosswalks High visibility crosswalks Optimal placement Advance stop/yield bars Signing Florescent yellow-green for pedestrian warning signs Rectangular Rapid Flash Beacon (RRFB) Pedestrian crossing islands
ZONE SYSTEM Frontage Sidewalk Curb Furniture
HIGH VISIBILITY CROSSWALKS
SIGNING
RAISED ISLANDS Pedestrian pass through on channelization island Photo Source: Mark Doctor, FHWA
SIGNING RRFB & CROSSING ISLAND
AVOID EXCESSIVE USE OF SIGNS
PEDESTRIAN ACCOMMODATIONS WHAT S GOOD WHAT CAN BE IMPROVED?
MARK CROSSWALKS WHERE RAMPS INTERSECT LOCAL ROADS
DESIGN INTERCHANGES FOR BICYCLISTS I-75 exit ramp to Bruce B Downs Blvd Tampa FL Photo Source: Mark Doctor, FHWA
On-Ramps Off-Ramps INTERCHANGE CASES DDIs SPUIs Roundabout
ON-RAMPS
ISSUES ASSOCIATED WITH FREE-FLOW ON-RAMPS
TREATMENTS FOR SINGLE-LANE ON-RAMPS
GREEN BIKE LANE Ocean Park Blvd, Santa Monica, CA
TREATMENTS FOR DUAL-LANE ON-RAMPS
TREATMENTS FOR DUAL-LANE ON-RAMPS
TREATMENTS FOR DUAL-LANE ON-RAMPS
TREATMENTS FOR DUAL-LANE ON-RAMPS
OFF -RAMPS
ISSUES ASSOCIATED WITH FREE-FLOW OFF-RAMPS
SIGNING AND STRIPING TREATMENTS FOR FREE-FLOW RAMP INTERSECTIONS
PREFERRED TREATMENT FOR FREE-FLOW RAMP INTERSECTIONS
OFF RAMP SIGNING
CAN PEDESTRIAN BE ACCOMMODATED? Neighborhoods Malls Costco
ISSUES ASSOCIATED WITH SIGNALIZED INTERSECTIONS
COMMON INTERSECTION TREATMENTS FOR PEDESTRIANS
INTERCHANGE GEOMETRY
HIGH SPEEDS, POOR VISIBILITY
WHAT S GOOD AND WHAT CAN BE IMPROVED UPON? Could have made this more of a right angle Tight right angle Could make this tighter radii
BEFORE & AFTER Flat angle = wide crossing & high-speed turns Tight angle = short crossing & slow speed turns Red arrow = old crosswalk Green arrow = new crosswalk Old ramp alignment Springfield OR
TEE IT UP
PREFER SLOW SPEED, RIGHT ANGLE URBAN DESIGNS
DESIGN DETAILS SLIP LANES W/ISLAND Tighter angle 55 to 60 degree angle between vehicle flows. 40 Old Way New way High speed, head turner = low visibility of pedestrians Slow speed, good angle = good visibility of pedestrians
RIGHT-TURN SLIP LANE - DETAILS Cut through medians and islands 2:1 length/width ratio 55 to 70 between vehicular flows. Crosswalk one car length back 25 to 40 radius depending on design vehicle Long radius followed by short Bicycle lane 150 to 275 radius
ALTERNATIVE INTERSECTIONS/ INTERCHANGES INFORMATION REPORT DIVERGING DIAMOND INTERCHANGE INFORMATION GUIDE (COMING LATE OCTOBER 2014)
WHAT IS A DIVERGING DIAMOND INTERCHANGE? An interchange form that allows two directions of traffic on the crossroad to temporarily cross to the opposite side to gain access to and from the freeway more easily
FHWA VIDEO ON HOW A DDI WORKS
OUTSIDE VS. INSIDE PEDESTRIAN PATH Pedestrian facilities on the inside minimizes conflicts with left-turning traffic to and from the freeway and allows crossing the interchange in all directions (along the arterial and crossing the arterial) For underpass DDIs, existing center bridge columns may dictate putting pedestrian walkways on the outside
PEDESTRIAN VEHICLE CONFLICT POINTS Outside Walkway Center Walkway
PEDESTRIAN PATH IN CENTER Source: MoDOT
PEDESTRIANS DOWN THE MIDDLE Very positive feedback from user surveys Saves bridge width May require structural capacity considerations
DIVERGING DIAMOND INTERCHANGES Photo Source: Mark Doctor, FHWA I-44 at SR 13 Springfield, MO
PEDESTRIAN PATH ALONG OUTSIDE Source: MoDOT
PEDESTRIANS HAVE DIFFICULTY VIEWING IF THERE IS AN APPROPRIATE GAP IN APPROACHING TRAFFIC DDI I-15 at American Fork, UT Photo Source: Mark Doctor, FHWA
PEDESTRIAN S LIMITED VIEW OF APPROACHING VEHICLES Photo Source: Mark Doctor, FHWA DDI I-15 at American Fork, UT
PEDESTRIAN SIGNAL Limited Sight Distance - use Pedestrian Signal DDI Kansas City, MO DDI Kansas City, MO
ROUNDABOUTS AT INTERCHANGES Dog Bone Diamond Compared to signalized intersections, roundabouts require fewer lanes on the crossroad (no need for turn lanes) resulting in a narrower bridge Roundabouts can have either a true circular shape or a raindrop shape Raindrop-shaped islands eliminate direct U-turn movements (U-turns can be made by circulating around both roundabouts)
City of Carmel, Indiana Photo Credit: American StructurePoint, Inc. www.structurepoint.com
THE PEANUT INTERCHANGE
RETROFITTING EXISTING INTERCHANGES Photo Source: Mark Doctor, FHWA
PROVIDING PEDESTRIAN PATHWAYS AS PART OF AN INTERCHANGE IMPROVEMENT PROJECT West Vail, CO Photo Source: Mark Doctor, FHWA
CASE STUDIES
Queens, NY CASE STUDY: PEDESTRIANS AT INTERCHANGES (QUEENS, NY) Problem/Background Pulaski Bridge is a major connector between Queens and Brooklyn Intersection at the base of the bridge had heavy traffic volumes, frequent vehicle crashes and a history of complaints about pedestrian crossings Northbound double right turns during different signal phases No crosswalk on the south side of the intersection Crossing for high-volume bus to subway transfer Source: NYC DOT
Queens, NY CASE STUDY: PEDESTRIANS AT INTERCHANGES (QUEENS, NY) Solution To simplify the intersection, right turns from the bridge guided to service road A new crosswalk and three median refuge islands added Signal phasing changed to ease movement from bus to subway Road nearest bridge converted from a two-way to one-way street to reduce conflicts Lanes on Jackson Ave converted to 2 left-turn-only & 1 through lane Source: NYC DOT
Queens, NY CASE STUDY: PEDESTRIANS AT INTERCHANGES (QUEENS, NY) Results Clarified vehicular movements Improved pedestrian safety, circulation and access; Intersection brought into a neighborhood scale Travel times on Jackson Ave declined 29% in the morning and 23% in the evening peak times No bicycle or pedestrian injuries recorded in 17 months after implementation
GROUP EXERCISE
EXERCISE TASKS Work in groups 15 minutes for exercise List 3 items that are positive for pedestrian safety List 3 improvements that could be made to improve pedestrian safety Designate someone to report out
Restaurants Gas Station Business Complex N Fast Food Strip Mall Casino Hotel Gas Station Gas Station
INFORMATION Along both Arterials Strip malls Casino Business complex's Restaurants Hotels Heavy truck traffic Port north of interchange Pedestrians Walk N/S on overpass Walk along arterial N
LOOKING NORTH AT WB ON-RAMP
LOOKING NORTH @ WB OFF-RAMP
LOOKING SB FROM NORTH INTERSECTION
LOOKING SB @ WB ON-RAMP
LOOKING SB FROM OVERPASS
LOOKING SB @ EB ON-RAMP & EB OFF-RAMP
EB OFF-RAMP
SOUTH INTERSECTION LOOKING NORTH
NORTH OF OVERPASS N
REPORT OUT List 3 items that are positive for pedestrian safety List 3 improvements that could be made for pedestrian safety
PEDESTRIAN ACCOMMODATIONS WHAT S GOOD WHAT CAN BE IMPROVED? Sidewalk on bridge & main Road Dirt trails leading up to bridge and intersection No crosswalks at interchange High visibility X-walks at intersection N
LOOKING NORTH AT WB ON-RAMP
LOOKING NORTH @ WB OFF-RAMP
LOOKING SB FROM NORTH INTERSECTION
LOOKING SB @ WB ON-RAMP
Overpass Sidewalk LOOKING SB FROM OVERPASS
LOOKING SB @ EB ON-RAMP & EB OFF-RAMP
AERIAL EB ON-RAMP & EB OFF-RAMP PEDESTRIAN ISLAND
EB OFF-RAMP
SOUTH INTERSECTION LOOKING NORTH
QUESTIONS / RESOURCES Bicycle and Pedestrian Safety Needs at Grade-Separated Interchanges http://www.bikewalktwincities.org/sites/default/files/interchange_fi nal_report_final_080508.pdf Alternative Intersections/Interchanges: Informational Report FHWA Publication No FHWA-HRT-09-060 http://www.fhwa.dot.gov/publications/research/safety/09060/ CalTrans Complete Intersection: A Guide to Reconstructing Intersections and Interchanges for Bicyclists and Pedestrians 2010 http://www.dot.ca.gov/hq/traffops/engineering/investigations/docs/ intersection-guide-bicycles-pedestrians.pdf Diverging Diamond Interchange Information guide Coming Late October 2014