If its a Happytime thats it...
If its the stock 44t sprocket on a 26" wheel it won't last long at 30 anyway...
Assuming 26" tall wheels with a 44t sprocket, 26mph is 6000rpm, 30 is nearly 7000. A bit high for the stock HT unless its its fully sorted.
Fitting a 36t sprocket, then 30mph is just under 6000.
35mph or more is possible with more tuning and gearing.
40+ with a shift kit and a tail wind. I've hit over 45 with my 700c shifter bike.
At speeds approaching 30 you will need to use motorcycle grade protection, gloves, helmet and boots. Then disc or better brakes, and quality road tires. Front suspension is advisable.
Ask me why I know...