roads
(
215
)
design and construction
(
183
)
maintenance and repair
(
124
)
transportation
(
121
)
testing
(
102
)
bridges
(
101
)
planning
(
96
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management
(
90
)
pavements
(
82
)
usa
(
78
)
safety measures
(
60
)
congresses
(
54
)
evaluation
(
54
)
environmental aspects
(
50
)
highway engineering
(
44
)
traffic safety
(
41
)
states
(
39
)
pavements, asphalt
(
37
)
test
(
37
)
traffic signs and signals
(
37
)
highway departments
(
35
)
traffic engineering
(
34
)
concrete bridges
(
32
)
data processing
(
32
)
transportation planning
(
32
)
specifications
(
31
)
highway planning
(
30
)
method
(
29
)
traffic flow
(
29
)
laboratory
(
28
)