The initial consumption stimulus from lower oil prices may be fading, at least in the United States, according to the latest round of official data on traffic volumes and fuel sales. Traffic on California’s highway network was 2.6 percent higher in May than a year earlier, the state transportation department said. Growth was the same as April’s but lower than in March and February, and not much different from the long-term average of 2.5 percent. In Texas, sales of gasoline and diesel were up 2 percent in April and March compared with the same months the prior year, a far smaller increase than at the end of 2014 and start of 2015, according to the state comptroller. Nationwide gasoline consumption is running 300,000 barrels per day higher than last year, data from the Energy Information Administration shows, but the year-on-year gains have stabilized in the last three months. […]