Here's why:
* Subject-Verb Agreement: The sentence doesn't clearly establish who is the subject performing the action. Is it the driver blowing the whistle or the train blowing a whistle?
* Word Order and Structure: The placement of the words is confusing. "Blowing whistle loudly" is a participial phrase that modifies either the driver or the train, but it's not clear which.
* Missing Prepositions: The sentence needs prepositions to clarify the relationships between the elements. For example, "nearby" could be replaced with "near" followed by a specific object.
Possible Solutions:
* "The driver, who was blowing his whistle loudly near the road, was surprised by the train."
* "A train surprised the driver who was blowing his whistle loudly on the nearby road."
* "The train's whistle blew loudly, startling the driver on the nearby road."
By restructuring the sentence and adding appropriate prepositions, the meaning becomes clearer and the sentence is grammatically correct.