May/June
2001
Work-Zone
Traffic Control: Survey of Contracting Techniques
by Angela Johnson,
Lloyd Rue, Ted Burch, and Dick Clark
The final
number of traffic control devices needed for a work-zone project and
the final bill for those devices often vary from the initial estimates
of the required number and charge. And the variance is usually an
increase in the quantity and the price that adds to the state's total
contract cost.
These
facts stimulated a recent survey of the state departments of transportation
(DOTs) by the Montana Department of Transportation (MDT) and the Federal
Highway Administration's (FHWA) Montana Division to gain a comprehensive
perspective of state contracting techniques for work-zone traffic
control devices.
This
article summarizes findings from the survey, which was conducted in
spring 2000. Thirty-five state DOTs responded, providing a view of
current practices across the country. An analysis of the survey results
presents valuable insights that will help MDT and other state DOTs
to improve their procedures and save money.
Survey
Results
Methods
of Payment
Nine of 35 states use "unit price" (per each device or per
each day); eight use "lump sum" for all traffic control
measures and devices; 15 use a combination of lump sum and unit price;
and three states use up to three methods, including lump sum, unit
price, pre-established unit price, and incidental cost to the project.
Each method has advantages and disadvantages. Advantages of the unit
price per device method are:
Additional payments will not automatically be provided for
time overruns.
Bid prices are easier to track (when compared to lump sum).
A disadvantage
is that inspectors need to inventory devices frequently - even daily.
The advantages of lump sum payment, according to the responding states,
include:
The contractor estimates the number and type of devices and the contract
amount.
The contractor is solely responsible for marrying traffic control
plans with production rates and construction methods.
Change orders are limited.
Devices are not individually counted.
Contractors are paid the contract amount within contract provisions
for added work or overruns.
More up-front coordination between the state and the contractor
occurs.
|
Drums,
raised pavement markings, temporary signs, and a type III
barricade on an interstate construction project. |
|
Disadvantages
include:
The contract amount will be paid even if the contractor does not use
the estimated quantities.
The contractor is not directly paid for devices not estimated,
but required, by the contract.
The lump sum may be overpriced.
The bid may be front-loaded through the traffic control item.
The bid price is difficult to estimate.
The project manager loses leverage to recommend that the contractor
add additional devices.
Unbalanced
Bids
Eighteen states had no evidence of unbalanced bids, in which the total
bid is appropriate for the work to be done, but some unit prices are
either abnormally high or low. Another 10 states said that unbalanced
bids are rare. According to these 28 states, the absence of unbalanced
bids is largely attributed to subcontracting work-zone traffic control.
Of the
states that reported evidence of unbalanced bids, some reasons for
their occurrence are:
Front-loading of project payout.
Variations from the traffic control plan.
Inaccurate estimation of quantities.
Some
states with evidence of unbalanced bids reported that the amount of
money is too small to pursue; therefore, no abatement is undertaken.
Techniques
to address the potential for unbalanced bids include requiring a detailed
traffic control plan for each phase, ensuring accurate estimates,
carefully analyzing bids to detect reasons for unbalanced amounts,
rejecting and re-advertising bids when unbalancing occurs, disqualifying
offending bidders, and setting minimum bid amounts on certain items.
Change
Orders
In 18 states, change orders are not required unless the scope of the
project is changed. Nine states rarely see change orders. Some form
of negotiation or written justification from the project engineer
is required by the states that do not use change orders for traffic
control adjustments. In the states that use change orders to adjust
quantities or payments for traffic control devices, change orders
are typically issued when the change is ±25 percent of the
contract amount, when a value engineering proposal (requiring a multidisciplinary,
systematic analytical approach) is used, when an item has been omitted,
or when the project time has been extended. The most common explanations
for change orders include unanticipated factors, such as weather;
contractor-proposed changes to methods or sequences; changes in construction
phasing by DOT field offices; and correcting estimates that do not
reflect contractor operations.
Estimated
Quantities
Contractors
estimate quantities for traffic control items in only 10 of the 35
responding states. All 10 states are currently using a lump sum method
of payment. Contractors in a few of the other responding states estimate
quantities when proposing a phasing or sequencing change, when estimating
the signs needed in addition to the state's standard signs, when extra
work occurs, and when implementing a value engineering proposal.
When
the contractor estimates the quantities, the contractor is responsible
for the number, type, and cost of traffic control devices. This can
be an advantage to the state because the state can save time by eliminating
the need to develop a traffic control plan.
Disadvantages
include the potential for underestimating the number of devices needed
by the contractor and for disagreement between the state and contractor
about the adequacy of the contractor-developed traffic control plan.
In the
states that do not allow the contractor to estimate quantities, the
cost and quantities are estimated using various techniques and information
sources, including:
Historical data.
Past projects.
Good engineering judgment. Size of the project.
Average unit bid prices.
Development of a detailed traffic control plan.
Requirements from the Manual on Uniform Traffic Control Devices
and state specifications.
Cost per mile.
Estimates of quantities for the most involved stage.
Percentage of the total project cost for other items in lump
sum projects.
Conclusions
The survey results establish a base line for MDT and FHWA's Montana
Division to jointly plan and implement improvements to estimation,
bidding, and contract administration.
Three
actions are planned over the next year to improve the process in Montana:
Different bidding techniques for traffic control items will be evaluated
on selected projects.
Estimators from each highway district will convene to discuss
practices and to map an ideal process for estimation.
Guidelines for project nomination will provide recommendations
for appropriate bidding techniques for work-zone traffic control items
dependent upon work type.
MDT is
committed to increasing the quality of work-zone traffic control from
three perspectives: the highway user, the project manager, and the
contractor.
Improvements
in bidding and estimating techniques will permit project personnel
to concentrate on work-zone application and layout. These same improvements
can result in efficiencies to the contractors, who can tailor work-zone
traffic control to their production rates and construction methods.
A final benefit is the reduction of the state's cost for work-zone
traffic control through improved bidding and contract administration.
Angela
Johnson is a highway engineer in FHWA's Professional Development
Program. In her current position, she assists an operations engineer
by reviewing design and environmental documents for construction projects
in one district of Montana. Johnson and the other authors of this
article were members of a committee that conducted the survey to gather
and analyze data to determine a way to improve the procedures for
bidding on traffic control devices and to minimize unbalanced bids
in Montana. She has a bachelor's degree in civil engineering from
the University of Wyoming.
Lloyd
Rue is a highway engineer in FHWA's Montana Division. He is responsible
for geometric design, traffic engineering, and highway safety related
to the federal-aid highway program. He has a bachelor's degree in
civil engineering from Montana State University and a master's degree
from the University of California at Davis. He is a registered professional
engineer in California and holds a professional traffic operations
engineer (P.T.O.E.) certificate.
Ted
Burch is a highway engineer in FHWA's Montana Division and is
responsible for the managing the design, construction, and maintenance
of federal-aid highway projects in Montana. He has a bachelor's degree
in civil engineering from Michigan Technological University and a
master's degree in engineering from Tulane University. Burch is a
registered professional engineer in Louisiana.
Dick
Clark is currently working for Montana's chief engineer in the
areas of engineering systems application and engineering process improvements.
He has a bachelor's degree in political science from Northern Montana
College and a master's degree in business administration from the
University of Montana. Clark has held several positions in maintenance,
materials, and engineering in the field and at headquarters with the
Montana Department of Transportation.
Other
Articles in this Issue:
5-1-1: Traffic Help May Soon Be Three Digits Away
Using
the Dynamic Modulus Test to Assess the Mix Strength of HMA
The
ITS Public Safety Program: Creating a Public Safety Coalition
Handling
the Worst Crash Ever in Virginia
Moving
Ahead - The American Public Speaks on Roadways and Transportation
in Communities
Branding America's Byways
Travelers
Seek Byway Experiences
National
Work-Zone Awareness Week Commemorated Across the Nation
Work-Zone
Traffic Control: Survey of Contracting Techniques