The officer referred to the proper citation, I believe. Even if you could prove that she didn't signal, I think that you would still be found guilty of failure to yield. If you have a decent driving record you may get a reduction of points/fine. Never hurts to try if you can spare the time to attend court.
OHIO RULES AND LAWS (B) " The driver of a vehicle or trackless trolley approaching a yield sign shall slow down to a speed reasonable for the existing conditions and, if required for safety to stop, shall stop at a clearly marked stop line, but if none, before entering the crosswalk on the near side of the intersection,
or, if none, then at the point nearest the intersecting roadway where the driver has a view of approaching traffic on the intersecting roadway before entering it. After slowing or stopping, the driver shall yield the right-of-way to any vehicle or trackless trolley in the intersection or approaching on another roadway so closely as to constitute an immediate hazard during the time the driver is moving across or within the intersection or junction of roadways. Whenever a driver is involved in a collision with a vehicle or trackless trolley in the intersection or junction of roadways, after driving past a yield sign without stopping, the collision shall be prima-facie evidence of the driver's failure to yield the right-of-way. " from:
Lawriter - ORC - 4511.43 Right-of-way rule at through highways, stop signs, yield signs.
My bolding on
"or, if none" above, I believe makes this law applicable whether there is a Yield sign or not.
In Maryland, where I worked for the highway agency, the applicable rule has been for a long time referred to as "The
boulevard rule is a principle in
United States traffic law which states that the driver of a vehicle entering a highway from a smaller road or entrance (called the
unfavored driver) must stop and yield the
right of way to all oncoming highway traffic (the
favored drivers).
[1] The rule often comes into play in
road accident cases, when a court must determine if a driver is
negligent in causing a collision, due to his breach of the
duty of care imposed by the rule on the unfavored driver.
Maryland[2] is among the
U.S. states which follow this rule, but not all states have similar provisions in
statutes or
case law.
New York[3] applies the rule to traffic entering public roads from private driveways or alleys, but not where public roads intersect. "