Parking Garage Planning and Operation ROBERT A. WEANT Staff Engineer ENO FOUNDATION FOR TRANSPORTATION, INC. WESTPORT 1978 CONNECTICUT Copyright 1978, by the Eno Foundation for Transportation, Inc. All Rights are reserved under the International and Pan-American Copyright Convention. Any reproduction of this publication in whole or in part without our per­ mission is prohibited. Printed in the U.S.A. Library of Congress catalog card no: 77-95226. FOREWORD In 1947 the Eno Foundation published Traffic Design of Parking Garages, by Edmund R. Ricker, who also revised the monograph in 1957. This publication was the first to relate scientifically the geometry of parking structures to driver and vehicle performance in the interest of efficient traffic operations. There has been widespread use of Mr. Ricker's publication and many of the new theories and practices recommended in it have been implemented to the extent that they are now taken for granted. However, while the fundamentals have remained the same, the applications of them are changing with time. Thus the Eno Foundation published Parking, by Robert H. Burrage and Edward G. Mogren, in 1957 (which included two chapters on garages) and Parking Garage Operation, by Robert E. Whiteside, in 1961. Frequent requests for all of the above monographs have been received by the Foundation up to the present time. This con­ tinued interest and expressed concern about garage planning and operations led to publication of this current monograph on the subject. This fourth monograph on parking garages retains the funda­ mentals pioneered by the authors of the previous Eno Founda­ tion publications and redefines them in terms of current practices. Thus the Foundation wishes to thank these authors, especially Mr. Ricker, for the framework that they established, around which this book is written. Recognition is due also to Mr. Herbert S. Levinson and Mr. John J. Cummings, who reviewed the manuscript and contributed many constructive suggestions. The Foundation also wishes to express its deep appreciation to the many city officials and garage managers or operators who provided data for this analysis. Finally, the International Parking Congress and the National Parking As­ sociation were most cooperative in providing lists of garages and in urging their members to respondto the study's questionnaire. The Eno Foundation has published, over the years, 16 mono­ graphs on parking. A majority of these are no longer in supply; iii iv FOREWORD therefore, this publication attempts to cover as many aspects of parking as possible. It is hoped that it will be useful in solving current and future urban parking problems. ROBERT S. HOLMES President TABLE OF CONTENTS Page FOREWORD ....................................... iii LIST OF TABLES ................................... xi LIST OF FIGURES .................................. xiii CHAPTER I-INTRODUCTION .......................... 1 Trends ........................................ 1 Monograph Purpose and Method of Study ................. 3 Study Scope .................................. 4 Study Organization ............................. 4 Summary of Findings ............................... 5 Planning and Design ............................. 5 Land Use Compatibility ........................ 5 Location and Use ............................ 6 Parking Garage Access ......................... 6 Pedestrian Movement .......................... 6 Parking Garage Size ........................... 6 Parking Dimensions ........................... 6 Financing and Management ........................ 9 CHAPTER II-PLANNING CONSIDERATIONS ............... 11 Planning and Policy Context .......................... 11 Early Establishment of Objectives and Criteria ............ 12 Parking Policy Guidelines ......................... 13 The Parking Program Team ........................ 15 Parking Studies ................................... 15 Types of Parking Studies .......................... 16 Comprehensive Parking Studies ................... 16 Special-Purpose Studies ........................ 17 Parking Characteristics ........................... 17 Parking Supply .............................. 17 Parking Facility Usage ......................... 19 Trip Purpose and Parking Duration ................. 20 Parking Accumulation and Turnover ................ 20 Walking Distance ............................ 20 Estimating Demands and Needs ..................... 23 Parking Inventory ............................ 23 Parking Demands ............................ 25 V Vi TABLE OF CONTENTS Page Estimating Demand at a Single Generator ............ 27 Parking Rates ............................... 28 Evaluating Facility Usage .......................... 28 Factors Affecting Future Demands ................. 29 Impacts of New Facilities ....................... 29 Daily and Annual Usage ........................ 30 Reasonableness of Estimate ..................... 31 Feasibility Analysis and Program Implementation ............ 32 Economic Feasibility ............................ 33 Comparative Analysis for Break-Even Income .......... 34 Financing Methods .............................. 36 Private Financing ............................ 35 Public Financing ............................. 36 Cooperative Public-Private Approaches .............. 37 Parking As a Public Service ...................... 38 Implementation Considerations ..................... 38 CHAPTER III-GENERAL DESIGN GUIDELINES ............. 39 Site Location and Development ........................ 39 Accessibility ................................... 40 Pedestrian Access ............................ 40 Vehicular Accessibility ......................... 42 Site Efficiency ................................. 45 Site Size and Shape ........................... 45 Land-Use Compatibility .......................... 47 Height Limitations ........................... 47 Setback Requirements ......................... 48 Visual Screening ............................. 48 Landscaping ................................ 54 Surface Lot Versus Structure Parking .................. 55 Parking Structure Design Concepts ...................... 57 Building Systems ............................... 57 Modular Systems ............................ 57 Demountable Systems ......................... 58 Clear-Span Construction ........................ 59 Short-Span Construction ....................... 61 Underground Parking Structures .................. 63 Design Vehicle ................................... 64 Vehicle Trends ................................ 65 Dimensions and Operating Characteristics ............... 65 CHAPTER IV-FUNCTIONAL DESIGN AND PARKING GARAGE LAYOUT ......................................... 69 Access Design .................................... 70 Main Floor Facilities ............................. 70 TABLE OF CONTENTS vii Page Access and Reservoir Requirements ................... 70 Functions of Reservoir Space .................... 70 Desirable Intake/DischargeCapacities ............... 71 Entrance/Exit Capacity ........................ 72 Automatic Gate Control ........................ 72 Entrance/Exit Dimension Guidelines ............... 74 Entrance/Exit Safety .......................... 74 Parking Layout Design .............................. 76 Design Elements ............................... 76 Parking Stall Dimensions ....................... 77 Access Aisle Dimensions ........................ 79 Desirable Parking Dimensions .................... 83 Parking Layout Efficiency ......................... 83 Efficiency Comparisons ........................ 83 Parking Layouts ............................. 85 Compact and Special Purpose Parking Stalls ............. 87 Compact Stall Design .......................... 87 Parking for the Handicapped and Bicyclists ........... 88 Planning and Design Details ........................... 89 Ceiling Height ................................. 89 Drainage and Plumbing ........................... 91 Lighting ..................................... 91 Desirable Light Levels ......................... 92 Ventilation ................................... 93 Carbon-Monoxide Hazard ....................... 93 Air Exhaust-Intake Requirements ................. 93 Carbon-Monoxide Detection ..................... 94 Parking Garage Heating ........................... 95 Floor Markings and Stall Delineation .................. 95 Alternative Marking Methods .................... 95 Signing ...................................... 96 Use of Color Coding .......................... 97 Changeable-Message Signs ....................... 97 Timing Sign Plans ............................ 97 Safety and Security ............................. 98 Active and Passive Security ...................... 98 Stairwell and Elevator Security ................... 99 Nighttime Security ........................... 100 Security Patrols and Surveillance .................. 100 Audio Surveillance Systems ..................... 100 Fireproofing and Control ....................... 101 CHAPTER V-VEHICULAR INTERFLOOR TRAVEL SYSTEMS ... 106 Ramp Systems ................................... 106 Analysis of Ramp Movements ....................... 107 Clearway and Adjacent Ramp Types ................ 107 viii TABLE OF CONTENTS Page Concentric Versus Tandem Ramp Design ............. 108 Parallel Versus Opposed Ramp Design ............... 108 Geometric Ramp Types ........................... 109 Straight Ramp Systems ........................ 109 Split-Level or Staggered-Floor Systems .............