Technology enabled parking meters

You are finding a parking somewhere - somewhere that still does traditional parking coupons? You will be off to a restaurant for dinner and don't know who much hours or value of coupon you should tear off. 1 hour, 2 hours? Well, some parking meters in the United States can be as conventional as parking coupons that are still used in parts of Singapore. I know the parking meters in San Francisco, Sunset area, still use conventional parking meters where you insert the value of coins equivalent to the total time you think you need the lot space for. Imagine you park few blocks away and need to go back to the parking meter to insert more coins to extend your parking or think of the frustration you have when you have already paid for 1 hr of parking but only use 10 minutes of it.

How nice if you get texted in your cellphone when the time in the parking meter is running out and you can "feed" the parking meter remotely via credit card. Being tested in Vancouver, such a service adds conveniece to you and will increase the city's revenue without costing much.

Now, when can we see that in San Francisco and Singapore ?