Work orders and GIS in the field: quantifying cost savings at the city of Arlington, Texas
Estimating Potential Savings with MDCS
Work flow diagrams were prepared to understand the tasks and staff effort associated with each
step in the work order process. Based on this analysis, three primary work activities were
identified that would generate cost savings using computers in the field.
- Meter Service Work Orders: customer service clerks would save time by not having to
enter the work order close-out information provided by the Meter Service field crews
after they completed a work order. Instead, the crew would enter the data using their
mobile computers directly from the field.
- Field Operations - Investigation Work Orders: the Service Specialists who perform
field investigations that result in the creation of work orders would save time by typing
information directly into the computer rather than manually filling out a work order form.
Additional time savings would occur because clerks would no longer have to enter the
information from the work order forms submitted by the Service Specialists.
- Field Operations - Sewer Stop Work Orders: the night crew would save travel time by
being able to access work orders and maps from the field rather than driving back to the
front office to access GIS maps and records of the sewer system.
With these three work activities isolated, estimates were prepared of the savings in staff time and
staff cost that Water Utilities would realize by implementing the MDCS. It was estimated that
with the MDCS solution Water Utilities could save $268,650 per year. Table 1 reports the
estimated time and cost savings for each activity.
Table 1Estimated Annual Time and Cost Savings
| Activity |
Quantity of Work Orders |
Time Savings per Work Order |
Hourly Rate |
Total Estimated Annual Savings |
| Meter Service Work Orders |
59,435 per year |
17.2 min. |
$15/hour (includes overtime pay) |
$255, 570 |
| Investigation Work Orders |
4,200 per year |
Service Specialists: 2 min. Clerks: 7.5 min. |
$18/hour $10/hour |
$2,520 $5,250 |
| Sewer Stop Work Orders |
295 per year |
20 minutes on 50% of the work orders |
$108/hour (staff and equipment costs) |
$5,310 |
| TOTAL |
$268,650 |
Comparing Costs and Savings
The cost for Arlington Water Utilities to implement the MDCS and field computers included
one-time capital cost and annually recurring operating costs. The total capital cost for
implementing the MDCS and field computers was $244,720. Table 2 summarizes these costs.
Table 2Estimated Costs for Implementing MDCS Solution
Water Utilities prepared a cost justification that demonstrated the department could save
$268,650 in work effort each year if it implemented the MDCS but that its total capital cost for
the system would be only $244,720. The new system would pay for itself within 1 year and as a
result was approved for implementation.
Arlington's MDCS Technology Architecture
Providing field access to the City's work order mainframe required that Arlington implement a
wireless Mobile Data Communications System (MDCS). The MDCS had two primary
objectives:
- Establishing a message switch or gateway that passes radio frequency (RF) data
between the mobile field computer and the City's IBM mainframe
- Implementing an efficient messaging system that would not overwhelm the wireless
RF environment
Initially the City of Arlington thought the MDCS would employ cellular digital packet data
(CDPD) telecommunication services purchased from the telephone company and a standard
email communication system that uses a SMTP (simple mail transfer protocol). Upon a technical
investigation of these assumptions, the City learned of limitations altered their initial technical
assumptions and approach.
* The MDCS solution required the implementation of a wireless message switch or gateway which was cost shared
by 2 other City departments who would use the gateway for other purposes. This resulted in a 3-way split of the cost
based on each department's proportional use of the system.
Since CDPD is a commercially shared radio frequency, the City realized that they would have no
control over traffic volume. If CDPD was used it could result in an over-saturated RF line that
could interrupt data communications between the field and the mainframe. In the face of this
limitation, it was decided to take advantage of an existing radio tower and radio frequency
register with the FCC that was owned by the City to establish a private, dedicated radio
communications environment. An additional benefit of this approach was the City saved the
$49/month/mobile PC cost that would be charged to use the CDPD service.
