This document provides an agenda and overview for a two-day training on fundamental concepts of roadway design and access control in Puerto Rico. Day one will cover introductions and several chapters from the 1979 Puerto Rico Highway Design Manual, including typical sections, basic design elements, and intersections. Day two will cover additional chapters on traffic barriers, traffic control devices, pedestrian facilities, and contract plans. The training aims to provide knowledge of PRHTA road design policies and procedures, covering factors of highway engineering and traffic related to geometric design, typical sections, structures, traffic control, and pedestrian facilities.
3. Tópicos Cubiertos: Día 1
1. Módulo i: Centro de Transferencia de Tecnología de Transportación
2. Módulo 1: Introducción y Trasfondo Histórico: Leyes y Reglamentos Aplicables
3. Módulo 2: Manual de Diseño de Carreteras del 1979
• CAPÍTULO 1: Criterios Generales de Diseño
4. Módulo 2: Manual de Diseño de Carreteras del 1979
• CAPÍTULO 2: Secciones Típicas
5. Módulo 2: Manual de Diseño de Carreteras del 1979
• CAPÍTULO 3: Elementos Básicos de Diseño
6. Módulo 2: Manual de Diseño de Carreteras del 1979
• CAPÍTULO 4: Intersecciones
4. Agenda: Día 2
8:00 Registro
8:30 Bienvenida
8:35
Módulo 2:Manual de Diseño de Carreteras del 1979
• CAPÍTULO 8: Vallas de Seguridad y Terminales
10:00 Receso
10:15
Módulo 2: Manual de Diseño de Carreteras del 1979
• CAPÍTULO 8: Dispositivos de Control de Tráfico
12:00 Almuerzo
AM
5. Agenda: Día 2
1:00 Módulo 2: Manual de Diseño de Carreteras del 1979
• CAPÍTULO 15: Facilidades Peatonales
1:20 Módulo 2:Manual de Diseño de Carreteras del 1979
• CAPÍTULO 19: Planos de Contrato
1:40 Módulo 3: Reglamento para el Control de Accesos y Obras o Facilidades de
Contrucción en las Vías Públicas de Puerto Rico
2:45 Receso
3:00 Taller
3:55 Clausura
PM
6. Acrónimos
AASHTO
ACT
ADA
ADT
DHV
DOT
ESAL
FA
FHWA
LPAU
MUTCD
OGPe
PRHTA
TCD
American Association of State and Highway Officials
Autoridad de Carreteras y Transportación
Americans with Dissability Act
Average Daily Traffic
Design Hourly Volume
Department of Transportation
Equivalent Single Axle Load
Federal Aid
Federal Highway Administration
Ley de Procedimiento Administrativo Uniforme
Manual on Uniform Traffic Control Devices
Oficina de Gerencia de Permisos
Puerto Rico Highway and Transportation Authority
Traffic Control Device
7.
8. Contenido:
Manual de Diseño de Carreteras, HDM (1979)
1. General Design Criteria
2. Typical Sections
3. Basic Design Elements
4. Intersections
5. Interchanges
6. Bridges
7. Pavements
8. Traffic Barriers and Fencing
9. Traffic Control Devices
10. Lighting
11. Highway Drainage
12. Soils
13. Utilities
14. Landscaping
15. Pedestrian Facilities
16. Field Survey Data and Photogrammetry
17. Environmental Considerations
18. Route and Project Planning
19. Contract Plans, Specifications and Estimates
20. Computer Programs
21. Administrative Procedures for Projects Design
9. Objetivos
• Proporcionar un conocimiento básico de las políticas de diseño de
carreteras y procedimientos del Manual de Diseño de 1979 de la
Autoridad de Carreteras y Transportación (ACT).
• Mostrar los factores envueltos en la ingeniería de carreteras y tráfico los
cuales están relacionados con:
• Diseño geométrico
• Elementos de secciones transversales
• Estructuras
• Dispositivos de control de tráfico
• Facilidades peatonales
10. Alcance de la Presentación:
Capítulos HDM del 1979 actualizados con
publicaciones técnicas de la AASHTO, USDOT, FHWA y ADA
CAPÍTULO 1: Criterios Generales de Diseño
CAPÍTULO 2: Secciones Típicas
CAPÍTULO 3: Elementos Básicos de Diseño
CAPÍTULO 4: Intersecciones
CAPÍTULO 8: Vallas de Seguridad y Terminales
CAPÍTULO 9: Dispositivos de Control de Tráfico
CAPÍTULO 15: Facilidades Peatonales
CAPÍTULO 19: Planos de Contrato y Especificaciones Estándar
*Capítulos cubiertos
11.
12. Problemas de Seguridad en las Carreteras
1. Obstáculos a la orilla de la carretera
2. Condiciones de la superficie del pavimento
• Deterioro / defectos
• Pérdida de fricción
3. Secciones transversales de ancho reducido
• Distancia lateral libre de objetos (“clear zone”)
• Medianas
• Terraplenes y cortes
4. Problemas de control de acceso
13. Problemas de Seguridad en las Carreteras
(cont.)
5. Diseño de intersecciones
• Carriles de viraje confusos
• Puntos ciegos / falta de visibilidad
• Dispositivos de control de trafico o rótulos
inadecuados
6. Zonas de trabajo
• Objetos y zonas de trabajo sin proteger
• Marcado pobre
• Rótulos no visibles e inadecuados
7. Limitaciones en el diseño de las carreteras
8. Conflicto con peatones y ciclistas
14. Establecer Necesidades
de Seguridad en las Carreteras
1. Identificar zonas de peligros y sus condiciones
2. Realizar una auditoria de la carretera
a. Recolecte y analice datos sobre el record de seguridad
• Reportes policíacos / base de datos de choques
• Registro de quejas de usuarios
• Record de mantenimiento
• Archivos de video de la carretera
• Planos de construcción
b. Crear un diagrama de condición del lugar
• Familiarizarse con las condiciones de la zona
• Observar la operación del trafico
• Recolectar información y dimensiones
• Identificar las deficiencias de seguridad
15. Establecer Necesidades
de Seguridad en Carreteras (cont.)
c. Seleccionar y llevar a cabo estudios para la zona
• Volumen de tráfico y velocidad de operación
• Distancia de visibilidad
• Capacidad de la carretera e intersección
• Tiempo de respuesta de servicios de policía y emergencias para
despejar incidentes
d. Evaluar los resultados del estudio
e. Determinar las deficiencias operacionales y de seguridad
f. Identificar mejoras significativas de seguridad y de operación
para el lugar
g. Escoger las mejoras apropiadas de acuerdo a un análisis de
costo-efectividad, reducción potencial, etc.
16. Establecer Necesidades
de Seguridad en Carreteras (cont.)
3. Establecer prioridades para la implementación del proyecto
en la red
4. Programar y ejecutar proyectos de seguridad
5. Evaluar efectividad de las mejoras de seguridad
implantadas
17. Propósito de Barreras
• Proveer un escudo a un obstáculo
• Prevenir penetración a la zona aledaña a la
vía de rodaje
• Redirigir vehículos
• Reducir la severidad del accidente
19. NCHRP Report 350
• Describes the vehicles to be used in testing, the test
conditions, and the instrumentation that will be used in
testing the hardware
• Testing criteria are hardware-specific that require multiple
tests under different impact conditions
• Six levels of testing (TL1 to TL6)
• Levels 1, 2, and 3 are applicable for both permanent and
temporary barriers used in work zones for car and pickup trucks
• Levels 4, 5, and 6 are intended for permanent barriers and
considers truck vehicles
20. Criterios de Evaluación de Dispositivos
de Seguridad
1. Parar gradualmente el vehículo
2. Redirigir de manera segura un vehículo que impacta de
manera frontal
3. Redirigir de manera segura un vehículo que impacta el
costado de dicho dispositivo
4. Escombros no deben penetrar el compartimiento del
vehículo
5. El vehículo no debe penetrar el tránsito en carriles
adyacentes
23. Barrier Warrants
• Subjective analysis
• When hitting a obstacle or running off the road is considered more
objectionable than the barrier itself
• Does not consider cost of installing a barrier vs. unshielded conditions
• Benefit / cost analysis
• Evaluate design speed and traffic volume in relation to barrier need
• Remove or reduce area of concern so that it no longer requires
shielding
• Install an appropriate barrier
• Leave the area of concern unshielded
28. Deflection Characteristics
a. Flexible systems
Three-strand cable
W-beam (weak post)
b. Semi-rigid systems
Box beam
Blocked out W-beam and
Thrie beam (strong post)
Modified Thrie beam
c. Rigid systems (concrete or
masonry)
Safety shape
F-shape
Vertical
Single-slope
29. Barreras Flexibles
• W-beam weak post
• Three-strand steel cable
• Deflexiones de impacto altas: 8 a 17 pies
30. Three-strand Cable
• Steel cables mounted on weak posts
• Redirects vehicle after tension is developed in the cable
• Advantages
• Low initial cost
• Low deceleration forces
• Minimized sight distance problems
• Disadvantages
• Periodic monitoring of cable tension required
• More barrier damage in a typical accident
• Needs more clear area behind the barrier
31. W-Beam (Weak Post)
• Behave like cable system, but with less deflection
• Posts serve primarily to hold the rail at the proper elevation
• Modified system w/ back-up plates tested at TL-3
• Advantages
• Low initial cost
• Low deceleration forces
• Disadvantages
• More barrier damage after a
typical accident
• Vulnerable to vaulting
• Lateral deflection is 2.225 m
32. Barreras Semi-rígidas
• W beam steel strong post (blocked out)
• W beam wood strong post (blocked out)
• Box Beam - deflexión de 2’ a 4’
• Thrie-beam strong post with notch
• Vehículos con altos centros de gravedad
33. Box Beam (Weak Post)
• Achieves resistance through combined flexural and tensile resistance of
box beam
• Posts break away and distribute force to adjacent posts
• Disadvantages
• Sensitive to mounting height and
soil irregularities
• Numerous parts and bolts
may become a maintenance
problem
• Relatively expensive
weak-post barrier
34. Blocked Out W-beam (Strong
Post)
• Minimizes vehicle snagging
• Reduces vaulting over barrier
• Achieves resistance through combined flexural and tensile stiffness of
rail and shear strength of posts
• Tend to remain functional after moderate collisions
37. King Block
• Cumple con NCHRP 350 TL-3
• Liviano (8 lbs)
• Más duradero que bloques de madera o acero
• Costo efectivo por ser reusable y reciclable
38. Blocked Out & Modified
Thrie-beam
• Similar to W-beam, but with deeper, stiffer, and additional corrugation
rail
• Allows higher rail mounting, making it better able to contain larger
vehicles
• Modified Thrie beam – reduces likelihood that a vehicle roll over barrier
• Effective with large pick-up truck and school buses
45. Consideraciones al Seleccionar una
Barrera
• Integridad estructural/desempeño
• Deflexión máxima lateral
• Costo inicial
• Costo de reemplazo
• Tiempo de reemplazo que le toma a la brigada de
mantenimiento
• Costo del inventario/aspecto modular
• Facilidad de instalar y remover
• Estética
46. Diseño de Barreras
Elemento Estándar - Consideraciones
• Velocidad
• Pendiente parte frontal y posterior de la barrera
• “Shy line”
• “Length of Need” (LON)
• Angulo de penetración
• Distancia al objeto fijo
47. Performance Capability
• Passenger cars and light trucks for low severity impacts: TL-
2
• Poor geometrics, high volume, and heavy trucks: TL-4 or
better
• Low-volume / low speed: lower than TL-3
58. Reglas Generales: Localización
Barrera Longitudinal
• Distancia lateral entre la barrera y el peligro
• 2 pies (0.6 m) mínimo
• Distancia longitudinal entre barreras para proveer
escudo para peligros aislados (poste de alumbrados
a 150 pies)
• Evitar instalar barreras discontinuas con “gaps”
entre barreras menores de 200 pies.
59. 5a. Lateral Offset L2
• Uniform clearance
• Barrier-to-obstruction distance and barrier
deflection must be considered
• Place as far from the traveled way as possible
• Shy Line Offset LS (Table 5.5)
Distance from the edge of the traveled way, beyond
which an object will not be perceived as an obstacle
and the driver will react to it
60. Distancia Lateral Mínima
(Shy Line Offset), Ls
Velocidad de Diseño
(mph)
80
70
60
50
40
30
Shy Line Offset, Ls
(pies)
12.0
10.0
8.0
6.5
5.0
3.5
63. 5b. Terrain Effects
• Curb affects trajectory of vehicle
• Guardrail-curb combination discouraged
• Curb height of no more 4in
• Add rubrail
• Slopes steeper than 1V:10H may cause
vehicle to go over or impact barrier too low
66. 5c. Flare Rate
• Barrier is considered flared when it is not parallel to
the edge of the roadway
• Pros
• Locate the barrier farther from the roadway
• Minimize driver’s reaction to an obstacle
• Reduce total length of rail needed
• Cons
• The greater the flare rate, the higher the approach
angle, the higher the severity
• Vehicle can be redirected back to roadway
68. 5d. Length of Need
Total length of a roadside
barrier needed to shield a
hazard
69. Placement Variables
• Lateral Extent of the Area of Concern LA:
distance from the edge of the traveled way to the
far side of the fixed object or to the outside of
the clear zone
• Lateral Extent of the Runout Length LR:
theoretical distance needed for a vehicle that has
left the roadway to come to stop
• Tangent Length from the Area of Concern L1:
selected by the designer (zero if no flare)
71. )/()(|
))(|( 21
RA
A
LLab
LLabL
X
• End treatment length is not included in calculation
• Adjust for nominal metal beams lengths: 3.8 or 7.6 m
Required length of need
in advance of the area of concern
)/()(
2
RA
A
LL
LL
X
74. Median Barriers
• Longitudinal barriers
• Separate opposing through traffic on high-
volume divided highways
• Contain and redirect passenger vehicles and
pick-up trucks
NCHRP 350
Recommended Procedures for the Safety Performance
Evaluation of Highway Features
75.
76. Devices for Median Barriers
1. Crash cushions involves rigid barriers with
cushions on each end, are effective but expensive
2. Open guardrail systems are less expensive, but
require more length, increasing the potential for
vehicles to hit it
3. Bullnose systems (closed guardrail envelopes)
wrap the guardrail completely around the hazard,
are the least expensive, but more dangerous of the
three designs
77. State Transportation Agency Median Design
and Safety Practices: Survey Results
• Approximately 76% of States have adopted
AASHTO policy as median design barrier warrant
standards
• Strong-post W-beam guardrail and concrete safety
shape are the most commonly used
• Innovative strategies
• Rumble strips on the inside paved shoulder
• Median side slope flattening
80. 2. Guidelines for Median Barrier Application
For high-speed, controlled-
access roadways with flat
traversable medians
Changes in AASHTO RDG
2006 - Figure 6.1
81. Guidelines for Median Barriers on High-Speed, Fully
Controlled-Access Roadways, Fig. 6.1
83. Deflection Characteristics
a. Flexible systems
Three-strand cable
W-beam (weak post)
b. Semi-rigid systems
Box beam
Blocked out W-beam and
Thrie beam (strong post)
Modified Thrie beam
c. Rigid systems (concrete or
masonry)
Safety shape
F-shape
Vertical
Single-slope
84. Concrete Barriers
• Most common rigid median barrier
• High-angle and high-speed impacts
• Airborne vehicle
• Reach top of wall
• Fixed objects on top of wall
• Snagging
• Separate from barrier
• Cargo box of high center of gravity vehicles may
hit fixed objects over wall
85. Disadvantages of Rigid
Barriers
• Stability problems for some vehicles especially at
extreme impact angles
• Vehicle redirection back into the roadway with little
loss of speed
• High occupant forces
• Elaborate drainage structures required
• Reduction of effective height and lowering of slope
breakpoint possible on pavement overlay
86. 4. Median Barrier
Selection Criteria and
Guidelines
Performance capability
Deflection characteristics
Site conditions
Compatibility
Life-cycle costs
Maintenance
Field experience
87.
88. 5. Median Barrier Placement
Recommendations
a. Terrain effects
b. Flare rate
89. Terrain Effects: Curbs
• Barrier face located within 9 in of curb’s face
prevents vehicle vaulting at 60mph
• Top of rail at 27in above the curb will make
impacts at lower elevations than normal
• Add rubrail to minimize snagging
• Align faces of barrier and curb and use normal
mounting height from curb bottom
90. Barriers on Sloped Medians
• Most desirable median: 1H:10V slope
• Section I – depressed median or with a ditch
• Section II – stepped median or with
separated traveled ways with significant
differences in elevations
• Section III – raised median or berms
99. 1. Performance Requirements
• Gradually decelerates vehicle to a stop or redirects
it when impacting end-on
• Safely redirecting vehicle that impacts side of
device, at mid-length and near the nose
• Test levels w/ 1.8k car and 4.4k pick-up
• TL-1: 30 mph
• TL-2: 45 mph
• TL-3: 60 mph
100.
101. 2. End Treatments
• Able to perform under head-on and side impacts
with no penetration inside vehicle
• Used to shield traffic on one direction
• Essential if barrier is within clear zone or in an area
likely to be struck
• Should not spear, vault, or roll a vehicle
• Must be properly anchored
102. End Treatment Types
1. Gating
• allows a vehicle impacting at an angle to pass
thought the device
• Length of need starts at 12.5 ft from impact head
• Traversable area of 75-ft beyond terminal by 20-ft
behind terminal
2. Non-gating – capable of redirecting along its
entire length
105. Flared Terminal Non-flared Terminal
• Terminals are flared away
from the traveled way
which creates an offset from
the tangent guardrail
• Used where the widening to
provide the offset for a
flared terminal is not
practical
112. Turndown
• Terminal turned down into the ground to prevent spearing
but may cause vehicles to roll over
• Rollovers are the most severe type of roadside crashes
(>25% of roadside fatalities)
114. Sloped Concrete End
Treatment
• Includes taper
• Used for impact speeds < 40 mph
• Locations where barrier is flared out
• ROW constraints
• Has not meet NCHRP 350
115.
116.
117.
118.
119. Barrier Anchored in Backslope
• Eliminates the exposed end of the guardrail
• Provides full shielding for the hazard
• Height of the guardrail is maintained until the ditch flow
line
• Guardrail is flared into the backslope
• Add rubrail for W-beam installation
• Guardrail is anchored in the backslope
• Slope into the face of the rail should be 1V:4H or flatter
122. Concept of Crash Cushions
• Gradually decelerates vehicle to a stop
• Absorb impact energy at a controlled rate
• Kinetic energy
• Transfer of momentum
• Stops a vehicle in a relatively short distance
• Shield end of median barrier or fixed object on gore area
• Shield fixed objects on either side of roadway
• Protection of highway work zones
123.
124. End Treatment y Dron de Seguridad en Plaza
de Peaje de Vega Baja
125.
126.
127. Cushions Types
• Plastically deformable
materials
• Crushing of front end
dissipates impact energy
• Rigid back-up or support
is needed
• Inertial barrier
• Expendable mass of
material (sand)
• No rigid support needed
• Analytically determined
design
133. Crash Cushions for Large
Vehicles
• All previously shown cushions are not
designed for heavy vehicles
• Gravel bed attenuator is still the most
suitable velocity attenuating design
134. Sand-Filled Barrels
• Transfer of momentum
principle
• No support is needed
• Standard modules from 0.2 up
to 2.1kip
• Wide hazards in low-
frequency impact areas
• Barrel's weight is determined
by its place within the array
135. Barrels Use
• Can safely decelerate vehicles ranging in weight from 1,810
to 4,410 lb and traveling at speeds up to 70 mph during
head-on impacts
• Low initial cost and requires no assembly
• Does not redirect errant vehicles away from the hazard
during angle impacts
• It should not be used if frequent angle impacts are expected
Breaks up during impact
Impacts close to corner
136.
137.
138.
139.
140.
141. 3. Selection Criteria and
Guidelines
• Each system has own unique physical and
functional characteristics
• Once it is decided that a shield is needed
• Site characteristics
• Structural and safety characteristics of systems
• Cost
• Maintenance requirements
144. 4. Placement
Recommendations
• Tested at flat, level surface
• Vehicle should strike at normal height
• Curbs should not be built near cushions
• Most attenuator systems must be placed on hard,
smooth pad or surface
• Delineate system to make it more noticeable to
drivers
146. Bridge Railings
Longitudinal barrier
• Prevent vehicle from running off a bridge or culvert
• Metal or concrete post and railing
• Safety shape
• Combination of metal and concrete
• Physically connected to bridge parapet
• No deflection when struck
147. 1. Performance Requirements
• Resist applied static loads w/o exceeding allowable
stress
• FHWA requires all railings on the National
Highway System to be a crash-tested design
AASHTO Standard Specifications for Highway Bridges
AASHTO LRFD Bridge Design Specifications
148. 2. Warrants for Railings
• All structures require some type of railing
• Preferably TL-3 or better
• Effective height
• Low-speed, low-volume may not need to meet full
AASHTO standards
• Rigid railing
• Approach guardrail
• Transition section
• Additional shield for pedestrians or cyclists
149. 3. Railing Types
• TL-1: Timber bridges
• TL-2: Thrie-beam railing
• Only non-rigid railing tested
• Mounting height of 22-in
• Post attachment yield on impact
• Low volume secondary roads
• Railing transition not needed
150. 3. Railing Types
• TL-3: Wyoming Two-tube railing
• Two horizontal rails
• Flush with 6-in curb
• Mounting height of 29-in (top rail)
• Modification with stronger rails successful at TL-4
153. 4. Bridge Railing
Selection Criteria and
Guidelines
Performance capability
Compatibility
Life-cycle costs
Field experience
Aesthetics
154. 4. Selection Criteria
• Performance: AASHTO specifications since 1964
• Compatibility: for different approach guardrail and
railing a transition is needed
• Life-cycle cost: rigidity and strength
• Field experience: crash and performance history
• Aesthetics: scenic areas and park roads
155. 5. Placement
Recommendations
• Full and continuous shoulder that maintains
clearance to roadside obstructions
• Provide flare rates when railing is inside shy
line distance
• Avoid 8-in or higher curbs in front of railings
• Railing requires special termination
156. 6. Upgrade of Railings
• Inadequate railing strength
• Designed before 1964
• Contain and redirect car impact at 60-mph and 25
degrees
• Snagging potential (open faced)
• Presence of curb or walkway
• Adequate approach rail to bridge rail transition
157.
158.
159.
160. Transitions
• Semi-rigid approach barrier joins a rigid
bridge railing
• Gradual stiffening of approach barrier
• Connection must be as strong as the
approach barrier
• Length should be 10 to 12 times the
difference in the lateral deflection
