The defeat of a November ballot measure and overly bullish economic forecasts are causing delays to the construction of new trolley lines and highway improvements, forcing a regional planning organization to seek new strategies to pay for its long list of transportation projects. A part of the San Diego Association of Government’s new approach is due to the failure of Measure A, an ballot item that, had it passed, would have levied a half-cent sales tax that was expected to raise $18 billion over 40 years to pay for transportation and infrastructure projects.