The post office chosen for this study during the months of July and August of 1993 was the North City West, zone 92130 in California. This office was chosen because at the time, this was the only DPS office in the San Diego area. North City West, zone 92130 consists of seven regular routes and three auxiliaries routes. Three methods where utilized over three weeks. One week, carriers used the composite bundle method: This is when a carrier has two bundles of letters in one hand, the DPS mail, and the mail that you have to case. The carrier then has her/his flats in his bag or in his arm. You look like your purposely wasting time when you're delivering mail because it is awkward and the two bundles of mail have to match up exactly. You're only complicating a simple process.The second week, the carriers in North City West used the VFC method: This is where the carrier cases all letter mail that is not in DPS order into his flat case. It's like what you do now, only with letter mail (falling all over) mixed with your flats. These two methods, at this point in time, are the only two methods approved by upper management and union officials for delivering automated mail.
The third week of the test assumes a more rational approach: the carrier cases the DPS mail. Though this method is not an approved method, for the sake of objectivity, it was included as a viable alternative. Casing the DPS mail, the method used in the third week, resulted in significant savings in office time without any increase in street time, and delivery accuracy improved since the mail was pre-sequenced, thereby reducing casing errors. Both of the two approved methods required more total time on the route, than casing in the DPS mail. Casing the DPS mail averaged less than 1 delayed letter per route per day, compared to the vertical Flat method which averaged about 83 letters per route, and in the composite method the carrier averaged 93 letters brought hack to the office. The carrier productivity level, using a method called DCEA, decreased drastically when the first two approved work methods where used, compared to the baseline, or to casing in the DPS mail.The study also points out that all the figures developed by the U.S.P.S. show 98% accuracy of the DPS mail as it comes off the machine, but this means nothing for delivery purposes. The only accuracy that counts, is that of the mail when it is presented to the carrier for delivery. This level of accuracy was significantly lower by the time it got to the letter carrier's case. Mail in the soft, cardboard trays break down or bounces and slides around, mixing the DPS mail. The old grey plastic trays are recommended. Mail in partially filled trays will slide out of order. Some trays, in transport to the case of the letter carrier from the machine, get tipped over, or the mail is sometime pulled off the machines incorrectly, or sent to the wrong routes or stations.